Aside: I think one of the things making this conversation difficult is the lack of nested quoting. I know nested quoting makes posts hugely long for little gain, but it does maintain the thread(npi) of a given conversation, and could maybe have prevented some of the merry-go-round phenomena that plague difficult discussions.
None of those were meant as examples of necessary Warlord tricks that couldn't be done, now. They were things a Warlord might do other than strict support-role functions - quite possibly in a few of the ways you describe, possibly in different ways using alternative uses/options to his support functions. That was in answer to Mouseferatu's question.
My point is, none of them for the most part can't be done NOW.
Then your point is moot. It had nothing to do with the question or my response. Mouseferatu wanted some examples of things a Warlord might do over and above his support (heal/buff) abilities. I gave some examples. Of course they're things that might already be done in other ways. They're alternative's to the class's main shtick, not part of it. Every class has many, many things it shares with other classes, as well as a few unique things.
Psionics is being added because its doing something the current casters can't yet do.
As strongly as I support the addition of Psionics, because I don't believe that merely not technically being a class in the 1e PH should have disqualified it from consideration for inclusion in the 5e PH, and because I believe that fans of psionics have as much right to having it available for their campaigns as I do to run campaigns that don't feature it, I can't help you argue for it for that reason. Psionics are a set of supernatural powers that prettymuch just do things magic can do (and not quite as many things). The proposed mechanics for the mystic aren't that different from the spell points module. The 'psionics is different' option could have psionic powers working in anti-magic fields and such, adding a 'Spock' to D&D's rock-paper-scissors aspect, but that's about as far as it'd go in really adding completely new stuff to the game. Doing things /differently/.
Much like the Warlord. If done well, it'll maybe do a few completely new things, a few things with different mechanical trappings, and a lot of things that can already be accomplished - but without supernatural agency.
What is the warlord going to add that a battlemaster with the proper skills and maneuvers can't do?
Umbran has already warned us about back-and-forth bickering instead of making progress in the discussion. In light of that, I see no reason to revisit this question, it's been answered many times.
Mouseferatu's question was a new angle on the topic, so I answered it.
Trust me, I don't care if you put giant hazard stickers, locked it on sealed pages between page 32 and 35, and had to sign a wavier to allow it; this ain't making it past playtesting for a normal class. Its a DM module, not a player class option.
Everything is a DM option. I decide the Wizard doesn't belong in my game, poof, it's gone. A class that's explicitly optional - not part of the Standard Game -
is entirely a DM resource, he must opt into it or it'll never see play.
If you compensate for his lack of versatility by making his buffs better than a clerics (say, inspiring word is a long range d8 buff and inspiring action grants 1d6 to all allies) he's going to break the assumed power curve for a character of that level (aka the bounded accuracy).
That's a balance issue. 4e balance was much, much tighter, and the warlord could be done under it. It'll be much easier under 5e.
The fear is that a warlord would be too good at his role (buffing and healing) to overcompensate for the fact he can't do what a spellcaster could do.
5e isn't so hung up on balance as to worry about stuff like that. There are classes that can do impressive DPR, or lots of other things, situationally or with resource expenditure, and others that can just DPR all day, virtually regardless of situation, with the only limiting resource being hps (staying up & fighting).
If the Warlord were, for some reason, limited strictly to healing & buffing, the designers would try to balance that with other heal/buff-capable classes who are also wildly over-versatile, to the degree expected in 5e, just like they've tried to vaguely balance other classes. Making that work in any given campaign, though, would remain the DM's responsibility. And, while I won't make light of that responsibility - balancing the existing classes is no trivial exercise - it's not one that the presences of the Warlord would make any harder, with extremes like the Champion (DPR, little else) and Moon Druid (heal/buff, offensive casting, utility casting/wildshape, wildshaped tanking, &c), for instance, already on the table. The Warlord would presumably be more versatile than classes like the Fighter, but less so that Clerics, Druids or Wizards - much like it was in 4e, just by much greater margins, since 5e has looser balance.
I'm suggesting that if given a choice, most people would want someone who can handle multiple different types of situations rather than hyperspecialize in just one.
So, for instance, they'd want a Ranger, who can also track and cast spells, or a Paladin, who can also heal and cast spells, as well as both being good at beating enemies down, over a Champion who can just beat things down?
Probably depends on the group.
he may not remove blindness, but maybe he could train the blinded character to compensate for it temporarily, for instance
Oh, a warlord can now cure blindness, even temporarily? Are we still aiming for "nonmagical", or are there examples of people being motivated to see again?
I don't see where you get 'cure' out of 'compensate for.' Think the Blind-Fight feat from 3.x, for an example of compensating for blindness without resorting to a supernatural cure or replacement for sight. No, the Warlord wouldn't just give people feats (that'd be soooo OP, I'm sure), that's just an illustration of the concept of compensating for blindness that's already been done in D&D, and is not unheard of in genre.
I've said before I don't care if they make a warlord, but I'm failing to see a place where one exists beyond "it was in 4e".
You're arguing against it pretty hard for someone who 'doesn't care.'

Seriously, though, if you haven't seen it after so much discussion and so many examples, you simply won't ever see it. Maybe you figure that since it was in 4e, there can't be any reason for wanting it besides '4venging,' just as it might seem there's no reason for opposing it but 'h4ting.' It'd be wonderful to get away from that edition-war era taint - until we do, all of D&D - the current edition, the game's history, the reputation of its community - is diminished.
Bully for you and your group. However, they were still not in the books or explicitly defined anywhere. If you and your group thought of them that way, they it merely highlights the way you and your group thought about the game. It doesn't present a universal truth - and the fact that so many D&D players were vocally uncomfortable about the notion of imposed 'roles' in 4E speaks volumes about the number of people who played D&D without them.
People complained about a lot of things that had never been issues before, and engaged in a lot of revisionist history, and generally were jerks all through the edition war. It's not a great place to point to for a foundation to an argument, other than, perhaps, 'we should really try not to engage in edition warring anymore.' Quite the opposite. If a lot of people were re-using a talking point or bit of rhetoric or newly-coined definition in the edition war, chances are there wasn't much /but/ edition-warring rancor behind it.
Ignoring the edition war, entirely, D&D had a long tradition of parties that included members of each of the 'Big 4' classes, as we've taken to calling them today: The Fighter, Cleric & Magic-User were the first 3 D&D classes, followed quickly by the Thief. The constituted de-facto party roles from the early days. In 1e AD&D, they were the 4 full classes, with other classes being sub-classes (and partial substitutes) for one or the other (and the monk and bard being oddballs). In 2e, the big 4 because class groups, with all the classes sorted under one or another. In 3e, the big 4 defined 'iconic class roles,' and other classes were able to fill in for one of them. And, again, the Monk & Bard were '5th wheels.'
5e is the first edition to intentionally try to give the appearance of breaking away from that. It still pays homage to the 'Big 4' as the only classes available in the Basic Game, but that's it. Once you get into the standard game, all classes are co-equal and have their own sub-classes, and no formally or informally defined link to one of the big-4. They still have certain contributions to make, with some classes being all about DPR as their combat contribution, and others being able to heal (because they have Cure Wounds in their spell list), and so forth. Some classes in effect stand in for one or another traditional class dynamically, while others can do so with build or planning, and a few sub-classes are locked into one. But all those are just a matter of mapping abilities to the traditional big-4 classes - 5e makes it pretty clear that it intentionally eschews designing classes with any sort of formal 'role' included, sticking to concepts (that, because of decades of tradition, mostly include being a bit like one of the big 4, with some variations).
It's no different to people insisting that D&D always used grids and miniatures to play. It didn't.
Grids were an innovation - in the early/mid 80s, AFAICR. Mini's were part of the game from it's beginnings in Chainmail and 0D&D (which /said/ it was a wargame using miniature figures right on the cover). To say that D&D 'always used minis' in the historical sense was correct - it always had rules for doing so. To say that everyone who played D&D always used minis would be presumptuous & unverifiable, at least. Back in the day, many of us (being quite young) couldn't afford to quickly build large collections of minis, for one instance, or didn't have space for a full-scale play surface to use them on, for another.
To emulate any Class from 4E you'd have to start about Level 3 in 5E.
Conceptually, perhaps, but it's not true of every class. Fighters pick a sub-class at 3rd, but Wizards pick their tradition at 1st, for instance.
4E generally started the Classes more powerful than other editions.
Also depends on the class. To use the wizard as an example, again, in 5e he starts out at 1st level with 3 dailies, a 4e wizard started with only one, and wouldn't get his third daily until 9th level. Even when he did get 3 dailies, the 4e wizard couldn't use them to choose one of several prepared spells and and cast it 3 times, he'd get to cast each daily he prepared exactly once. 5e casters have gained considerably in versatility & power relative to 4e, even as they've been brought down a bit from 3.5, an example of how 5e sorta split the difference among many editions. 4e did start everyone with more hps and more self-healing than 5e, but that has more to do with 5e aiming for shorter (some folks have mistaken them for 'easier') combats which doesn't require as much PC durability, than making characters in any sense 'less powerful.'
That's actually not true. A high-level fighter is in an excellent position to become a tank or a defensive "controller" for much the same reason he excels at DPR: grappling, like DPR, scales with number of attacks. Imagine a 12th level Eldritch Knight with the Enlarge spell, Str 20, and Heavy Armor Master, Shield Master, and Grappler feats.
While I personally like the idea of a grappling fighter build as a way of a exerting a little control on enemies, there's two small problems with that suggestion:
1) It's a little weird from a genre perspective: outside of a fairly specific Heracles/strongman archetype, you don't see a whole lot of 'wrestlers' going in against armed opponents and monsters in genre. When you do, it's even rarer to see them in armor, and I can't think of any case of a character in armor, with a shield, grabbing enemies with his free hand as a primary combat strategy.
2) According to the latest Sage Advice, grappling is an action, not an attack action (like it was in 3.x). While DMs are free to rule otherwise, hanging a whole archetype on favorable DM rulings isn't the most compelling case for that archetype being well-supported.
(He would of course be even better at his chosen role if he were an Eldritch Knight 11/Rogue 1 for Athletics Expertise, but that is neither here nor there.)
What, not a Champion for 'Remarkable' Athlete? ;P
Though I can see way some have an issue with that. The class is telling them what their PC is inspired by and its not a magical effect.
Actually the class was telling you what benefit you get from being inspired. What inspired you is not specified. Might be something worth working out between the players in question. Like any other potential character conflict, just not as serious as, say, the witch-hunter (Paladin) and the witch (Warlock).
Your LG Warlord is a major inspiration to my CN rogue who can barely tolerate him?
Sure, the Warlord criticizes your lack of discipline and your Rogue outdoes himself to prove him wrong. The more you resent him, the better it works. If you want a little character development, you can even modify it at some point. Have a moment where the Warlord develops some genuine respect for the Rogue, and the Rogue is inspired by the Warlord's new-found faith in him. It's all up to how the players RP their characters. If one is just there to sabotage the other, it won't go well.
Beyond that, nothing forces you to use a specific class to represent the archetype you want to play. In 4e if you wanted to be a defender and also a 'ranger' you could simply be a fighter and take a background/feat that granted access to the Nature or Dungeoneering feats... I suspect 5e can do the same thing.
5e is full of such options, yes! You have Backgrounds, which are open to DM additions. You have feats that pull a little bit of utility from a class. You have a few 'gish' sub-classes, like the EK. And you have 3.x -style multi-classing. Feats & MCing are 'optional,' but even without them, Backgrounds let you tack a little of one of the Big4, for instance, onto any character (Accolyte=Cleric, Sage=Wizard, Outlaw=Rogue, Soldier=Fighter), and others, like Outlander(Ranger), let you tack on a bit of the feel of other classes as well.
You can look to Soldier (for Rank) or Noble (for authority) and/or the Inspiring Leader Feat, for instance, as ways to tack a little Warlord onto any class, or the Battlemaster as a 1/3rd Warlord, the way the EK is a 1/3rd caster.
There's just no corresponding Class if you want to take the concept all the way.