I'm glad you two aren't in charge of publishing at WotC, or we wouldn't get anything! - after all, there's always someone who can think of a different way to do it.
IMX, folks who express this kind of attitude are often the same ones who think WotC is crazy for not having already called them, begging for them to take the lead in doing the thing.
Oh, look. The rest of your post goes on to show just how true that seems to be.
Oh, OK, I'll look:
The details of those is a design question I'm not qualified to answer.
Perhaps because I'm not a very good 5e designer, I can't at this stage quite see how those high level abilities would be "filled in" for a 5e warlord.
IDK. I've had a lot of conversations with pemerton, and he's mostly a pretty reasonable gamer - he does get highfalutin at times, but he did throw in some conscious humility there, at points.
I wonder which part causes so much of a problem is it Martial or Support or is it the combination of the two?
Obviously it's not either one by itself. The Bard, Cleric, and Druid all provide significant support, enough for a whole party to depend upon, and a great deal more, as well.
The Berserker, Champion, Battlemaster, Rogue & Assassin are all 'pure-martial,' with no supernatural abilities, at all (though some might argue against the first being entirely non-supernatural, because of Rage) - and several additional such sub-classes were added in SCAG without the least complaint.
The Paladin and, arguably, the UA A
rdentvatar, also already combine martial and support functions, albeit, with the support side being clearly supernatural for the most part.
Hmm... having said that, I suppose it /may/ be that a 'pure-martial' full class is anathema for some reason, just in itself, if only because 5e hasn't gone there yet. ...interesting thought.
But, for now, my guess would be that it's the combination of 'martial' (traditionally simplistic, choice-poor, and overshadowed as the party rises in level) & 'support' (a diverse and critical role traditionally best filled by full casters) /and/ the sole precedent of the Warlord being from 4e, an edition where
martial and 'caster' classes were not just theoretically balanced, but shared a rough parity. In order to be a viable support class, capable of stepping into the shoes of the traditional Cleric (or Bard or Druid), it'd have to closely rival the versatility, flexibility, power & resources of a full caster. Between that need, and the precedent of having been balanced neatly with those same three classes in it's only appearance, the Warlord could represent something so unique that people balk at the prospect of its introduction.
Do people really have that much problem with a martial class that does more than reduce hit points and makes an occasional ability check?
Without getting hung up on the technicality of 'ability check,' can you think of any martial classes like that in the history of the game from 1974-2006?