Wasn't talking about using the Warlord's reaction. I was thinking in terms of the Warlord using an action or a bonus action to grant an ally the ability to make an opportunity attack or move a certain distance (half dash?) using the ally's reaction on the Warlord's turn. If you are concerned that reactions are too hot a commodity, perhaps it should be an opportunity attack that is like a reaction but does not use the reaction, limited to one opportunity attack per round. This is exactly the way the optional rule for marking targets is stated in the DMG (page 271.) The opportunity attack is made with advantage and doesn't consume the attacker's reaction, but cannot be made if some effect prevents the attacker from taking reactions (e.g. shocking grasp.)
Yeah, that'd be a reasonable compromise: "if the target ally has not taken their reaction..." kind of thing. Would encourage the Warlord to prioritize initiative and trying to actually
lead the attack, which isn't a bad thing at all. (more on this at the bottom of the post)
With regard to restoring real hit points and standing up fallen allies, there are a couple of ways that could be done within the framework of 5e themes. There are the "special herbal poultices" of the "spell-less ranger" that are "free" healing potions. The Warlord could have an ability such that whenever the Warlord uses a healer's kit to stabilize an ally at zero hit points, the ally automatically regains one hit point.
I would be very hesitant, though, to give the Warlord an ability to restore a lot of hit points in combat.
It's a sticky issue. For some Warlord fans, the absolutely adamant perspective that Warlords should never have "real" in-battle healing is, essentially, people saying they don't actually want "the Warlord" to exist in their game. [MENTION=31506]ehren37[/MENTION]'s post, while somewhat more nuanced, is essentially that: why should people who don't play Warlords, and particularly un-fans or even anti-fans of the class, get to decide what it can and can't do? But then for other fans, whether or not the Warlord can grant "real," in-battle healing is a total non-issue, they don't give a crap. Such people have explicitly weighed in as such, earlier in the thread, though I'm not going to go digging just to get a reference.
Something to consider, here, is that you have structured it as "a lot" of HP. What is "a lot"? I assume something like 4e's Healing Surge (25% of max HP) would qualify as "a lot," but would rolling one Hit Die be too much? What about a static value, but limited to a number of uses per short rest (e.g. Int or Cha mod heal, for half proficiency mod uses/short rest)? If neither of those alone is too much, would they be too much together? (Obviously if either one alone is too much then the combination would also be.)
Or is it not quite specifically the amount per use, but the total amount over the day? E.g. you don't want Warlord heals to ever overshadow the amount gained from just rolling Hit Dice, or some other such standard?
I apologize if this sounds like an interrogation. Most people acting as the "opposition" (that is, the people who don't know the Warlord or who need/want to be 'convinced' to 'accept' it or w/e) tend to be vehemently, adamantly opposed to even the
thought of "real" healing from a Warlord. You, on the other hand, seem to be at least open to the possibility, simply skeptical about the execution, so I'm trying to determine how exactly you feel about the prospect of martial HP restoration.
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Now, to actually cover that "more below" thing I wanted to touch on. Warlords, at least in 4e, made their parties substantially more mobile. The shift, as you've noted, was one form of that, but tinkering with Initiative in one way or another was also an option. Things that affect Initiative in 5e are few and far between. It could be really neat if a Warlord class feature specifically interacted with that in a meaningful way, such as being able to swap places with an ally in the order, or having (say) Int-mod points which could be added
or subtracted from allies' Initiative rolls at the start of combat (that is, before any players have taken their turns).
Similarly, a high-level Warlord ability might allow the party to re-roll Initiative in the middle of combat. This could be quite powerful, since there are special features of several classes which key off the phrase "when you roll Initiative." The Warlord could then act as a way to
occasionally re-take/press the momentum of a fight; if it were keyed to a short rest, it could be seen as a moment of great inspiration for the whole party, but which requires everyone being on board together, and thus can't be demanded repeatedly without a break (though, of course, I'm sure people will still dislike it...) And really, I'm not even saying these would HAVE to be the thing to do. They're just one interesting way to explore the "planning," "coordination," and "inspiration" sides of having a Warlord in the party--even if they aren't the party face, they have a command presence on the battlefield and can make a substantial difference in a fight.
There are, of course, non-combat considerations. I still think the Grim World "Battlemaster" playbook (a supplement for Dungeon World) has a
bunch of really cool ideas to mine.