"Genre" arguments aren't my thing because it's never clear what genre is being discussed
The broader heroic fantasy genre in general, I'd think. Anything from low-fantasy & S&S to Lovecraft to High Fantasy, cinematic fantasy, and myth & legend.
And it is hard to call to mind a character who would arm himself with heavy armor and a shield, but not an actual weapon. It's odd. Not that I have a problem with the odd odd character concept, just with it being the only viable way to realize a much broader, more conventional concept. Though Sentinel helps, as well.
And thanks for the clarification, I somehow read multi-attack as 'extra attack.' Danger of having played too many version of the same game.

My faith in Sage Advice is somewhat restored.
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".
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.
First off, I really don't appreciate that any criticism of 4e is viewed by you as "h4ting." I'll GIVE you reasons to 4venge if you want, but my concerns are in 5e, and now. So knock off the "haters gonna hate" crap, it weakens your argument.
You suggested that the only reason I'd want a Warlord was because it was in 4e. If you think that sort of things weakens arguments, you might want to avoid it - and avoid reading it into others' posts - going forward.
Now, my problem with the warlord is not conceptual. The idea of an intelligence-based warrior has appeal, as does the idea of a leader class of some type. I like the marshal (weak as it was) and allowed it in 3e. Likewise, I liked Pathfinder's cavalier, which borrows some elements of "smart fighter/inspiring leader" as well. On pure basis of that, I hold nothing against the warlord. (I was also an advocate for the "every PHB1 class in 5e" stance, assassin, warlord, and illusionist included).
Love to see you suit your posts to match that assertion some day.
What I have problems with so far, I haven't seen a warlord suggested that I would allow in game. There are a number of reasons why. The biggest is that for all of 5e's "looser" form of balance, most warlords end up tossing out bonuses that wreck bounded accuracy.
That sounds like you've seen what the 5e Warlord class is going to be. Have you seen a playtest version we haven't, or are you just imagining a worst-case scenario? Could you maybe favor us with a best-case scenario for contrast?
Above all, I'm not seeing what a warlord brings to the game other than "battlemaster, but more powerful" or "bard, but nonmagical." Nobody has convinced me that there is a way to MECHANICALLY do a warlord that isn't going break the game in one or more ways.
I'm surprised you're so worried about balance in a game like 5e, especially as a psioinics fan and advocate for the not-magic version which'd introduce a supernatural power set as versatile/powerful as magic, but immune to some of the most dramatic checks that the DM can use against it.
So conceptually, I don't mind the idea. Mechanically, I haven't seen one suggested here or in the other thread that works.
Really, at this point, the conversation is, or should be, mostly conceptual. Design is in the designers' court, and shooting down spit-balled fan speculation about what a warlord mechanic might be like isn't that meaningful (however much fun it may be to shout 'pull' and blow away another dream).
Nor really am I feeling the game is lacking for not having one right now
I guess that's personal. If you don't want a Warlord or don't want to get too deep into the concept, then the lack of one, or the presence a barely-suggestive-of-a-Warlord a feat like Inspiring Leader or sub-class like Battlemaster, is probably adequate.
I can empathize: if I really wanted to play a psion, right now, I'd play a GOO Warlock and be fine with it, since I was never deeply into the distinctiveness and concept of past versions of Psionics. I'd have telepathy, and choose some mind-affecting spells, and re-skin the whole pact thing. Or I could go with a Sorcerer, make similar spell choices and call him a 'Wild Talent.' That'd be all the psion I'd need, and more.
But, I wouldn't expect a fan of psionics to whom psionic combat or psi not being magic or just the full range of things psionic classes have been able to do in past editions were critical aspects, to be satisfied with that.
(whereas I really want a good psionic and artificer class). So overall, I end up neutral. I just haven't seen anything much that doesn't sound like a DM headache.
Speaking of concepts that could break 5e if you assume the worst-case, the Artificer /makes magic items/. That's the concept. In 5e, magic items are very powerful, pretty rare, and almost entirely in the DMs bailiwick (healing potions seem like pretty nearly the only exception - certainly the only one I can call to mind atm). That's a major design stumbling block, and not one that I'd want to tackle, nor one that I would require anyone who wanted to see an artificer in 5e to solve before I'd allow that the class is worthy of possible development.
That said, I love the concept of the Artificer, have had a great time playing one, and playing alongside one, and would love to see what the designers could come up with to make one work in 5e. Afterall, the Artificer was present in the last two editions, and, while I never dealt with the 3.5 version, the 4e version was reasonably balanced, playable, and had a way around the magic-item-creation conundrum. I'm sure if editions as far apart on the balance scale as 3.x and 4e could both handle the Artificer, 5e certainly can.