I'm not sure that isn't just rhetorical, but you do bring up a point. There are really more than the two extreme camps. There are those who want the Warlord in 5e, those who want it purged from the game forever, those who might want something like the Warlord but find it some how not quite meeting their need...
Or there is the "Like the warlord concept, and wouldn't mind a class that fills a similar niche but adheres to the rules and fluff already established."
That'd seem to fit pretty well to the last one. Though, to be fair, the Warlord "fills a similar niche" in some practical senses (support, secondary melee, face), to classes that have existed for a long time, so there are pre-existing examples, by definition - unless you meant something else by 'niche.' The Warlord could very easily adhere to the rules already established - though most if not all classes do have abilities that are unique and/or exceptions to existing rules and there's no reason to think any new class would be any different. As to 'established fluff,' I'm not sure there is such a thing - campaigns and settings can vary quite a bit, as can how DMs interpret things, and re-skinning (short of changing mechanics) isn't entirely discouraged in 5e.
In short, a class that can be dropped into a campaign and won't change the dynamics of the game any more than any other class would.
The Warlord would almost certainly fall between the non-caster and caster sub-classes in impact on a campaign, being more flexible and filling a different niche than the former, while less versatile than the latter. Seems unlikely to disrupt anything. On the contrary, a campaign with a Warlord instead of a Bard, Druid, or Cleric will probably be a little easier for the DM to keep a lid on.
Warlords are children of 4e
Yeah, like I said, there are those who don't want the Warlord because 4e. The reasonable compromise lies in making it convenient for them to avoid the class, since they could never accept it in any viable form.
they were a class built around the concepts of 4e like healing surges
like HD in 5e.
an available module in 5e, though 5e uses movement/range/area precise to the foot, anyway.
5e's has even fewer actions
5e has Second Wind, Action Surge, 17 battlemaster maneuvers, Cunning Action, and a few other odds and end.
5e lacks many of those direct elements.
Actually, it has versions of all of them. Mostly dialed down to 2, with the names changed and the serial numbers filed off, but they're there. One of the subtler ways 5e tried to build on past editions.
They define things differently than 4e did. In 4e, being inspired meant being able to use a healing surge
Or gaining temps, or an action, or a buff, etc. Inspiring Warlord builds didn't just trigger surges.
or a bonus to a roll, or advantage.
Granting a bonus to hit in 4e could be shown a dozen different ways and amounts
Power, Feat, Enhancement, Untyped, not quite a dozen, no
5e lumps it all into advantage.
Except when it doesn't, with support-class abilities like Bardic Inspiration, Guidance, or Bless, for instance.
A 5e warlord cannot rely on the 4e definitions of abilities to define it. It must find an identity somewhere inside 5e's paradigm.
Not see'n the problem.
It can't demand Inspiring Word to work as it did in 4e anymore than a Fighter can demand Combat Superiority, or a Ranger Hunter's Quarry.
Sentinel and Hunter's Mark /do/ work though, just not exactly the same.
And, for instance, the 4e Ranger Had Hunter's Quarry as an ability he could use every round. Every ranger had it, every ranger used it or he was a fool, he'd have to wait to Paragon to even cheese up an alternate use for one die of it. Now, in 5e, a player who thinks "Y'know, Hunter's Mark just doesn't fit my vision, I'd rather go with Hail of Thorns and Ensnaring Strike," can never touch Hunter's Quarry. Going dark blue rather than light blue might make him sub-optimal, but he's still viable.
Now, those are also spells, but the Ranger has been using magic since it's first appearance in 0D&D - as nice as a spell-less ranger would be to have (and we did have an example), you can't begrudge him casting spells.
Point is, different, but not only still good, more flexible.
The question becomes how do we make the warlord concept fit 5e, not how do we make 5e fit the warlord.
OK, I have to just stop and review the above. You're making the case that 5e is so limited, unwieldy, unbalanced, inflexible, and generally wholly inferior a game, that it just can't model a class that 4e had /no trouble with at all/. That is an extraordinary claim, IMHO. I think I've answered most of your accusations against 5e fairly reasonably, above. It can, in fact, at least start to address all the aspects of the Warlord you claim it couldn't possibly deal with, just based on existing precedents.
BUT,
5e doesn't limit itself to precedent. Each class and ability is not built on some template. Every class has something unique going for it, some novel mechanic(s) whether as minor as a small bonus to untrained athletics checks, or as significant as recovering slots on a short instead of long rest. There's not some empty file cabinet in Redmond where every possible good 5e mechanic had been stored. There's not a finite amount of designer talent that has all been used up. 5e is, in fact, a wide open system with parsecs of design space available, especially for martial classes, of which there are only 5 sub-classes at the moment, and most of them quite similar, functionally (all filling the high-DPR niche in different ways).
AND, on top of that it, 5e has the Ultimate RPG Weapon: DM Empowerment. If the designers do let slip something that doesn't quite work, or doesn't quite work for a particular campaign or at a particular table, the DM can rule, right then and there, to bring it into line.
The question becomes how do we make the warlord concept fit 5e, not how do we make 5e fit the warlord.
Neither of those sound like the question based on all the above. Maybe, how do we create a great Warlord in 5e? Though, really, that's more a question for designers to answer.
The question at least, in this little exchange, seems more like: Will you, Remathilis, encourage the designers to explore more of the potential of 5e by bringing us a 5e Warlord that is even better, covers more concepts, and generally rocks the casaba in a way that makes the 4e Warlord at least nod approvingly, if not go into early retirement in shame? Or, will you continue to stonewall any attempt at moving the 5e Warlord forward, even at the cost of denigrating 5e as an inferior system, unable to handle a capable, balanced, viable, martial class that can adequately contribute to a party in a version of the traditional support role, /and/ undercut it's laudable (if a little smarmy and kumbaya) goal of being a version of D&D for everyone who's ever loved D&D, that will bring our fractured little community back together?
So 9 classes (FR player book containing the Swordmage was August), no sub-classes (but 20 'builds,'). 5e is way ahead by that scale. OTOH, a little over a year in, 17 classes, 60+ builds... Pace of release means a lot. 
