Hussar
Legend
Honestly, I think the Barbarian with it's Totem mechanics actually might be a better mechanical fit than the Battlemaster with its Superiority Dice. Note, you'd need to change the chassis a bit, since I don't want a Warlord with d12 HP. 
Imagine, instead of Raging, you get Stances. The stances can be limited to a certain number of times per day, or perhaps they refresh on a short rest. I'm spit balling here, but, at will stances would be too weak.
You could have an Inspiring Stance, a Bravura Stance and a Tactical Stance. At 3rd, 6th, 10th and 14th, your stance effect changes. Or, you might stick with the barbarian mechanics and have three different stances at each level, and let the player pick and choose. So, a Tactical Stance at 3rd level might let you grant a single attack or move as a bonus action. A 6th level Tactical Stance might grant movement to multiple allies. 10th level might be a bigger buff - if basic Warlords grant an initiative bonus, say, then a 10th level Tactical stance grants a bonus plus proficiency bonus to everyone within a certain range. At 14th level, maybe you can grant a full action to one character as a bonus action. Dunno, I'd have to let people who are far more mathy than me figure out the exact numbers here.
Stances could be bonus or full actions to activate, depending on how powerful you want them to be. Let the stances last for 1 minute. You can use a number of stances per day depending on your level.
Your base Warlord, like the base Barbarian would come with a handful of common abilities - ranged healing of some sort (I really do like the idea of allowing allies to spend Hit Dice in Combat with bonuses, plus maybe a bardlike bonus to all healing on short rests), a second attack per round, maybe a way to trade an attack for another character's attack or trade your move to move another character, some skill bonuses (I love the idea of granting bonuses similar to a Guidance Spell) to allies at 7th level and you're done.
I really don't see balance issues here. Sure, there could be if you're granting too many actions or too high of a bonus, but, none of this is inherently unbalanced. I'd also point out that all of this exists in other classes. Nothing is particularly new here, just combined in a new way.

Imagine, instead of Raging, you get Stances. The stances can be limited to a certain number of times per day, or perhaps they refresh on a short rest. I'm spit balling here, but, at will stances would be too weak.
You could have an Inspiring Stance, a Bravura Stance and a Tactical Stance. At 3rd, 6th, 10th and 14th, your stance effect changes. Or, you might stick with the barbarian mechanics and have three different stances at each level, and let the player pick and choose. So, a Tactical Stance at 3rd level might let you grant a single attack or move as a bonus action. A 6th level Tactical Stance might grant movement to multiple allies. 10th level might be a bigger buff - if basic Warlords grant an initiative bonus, say, then a 10th level Tactical stance grants a bonus plus proficiency bonus to everyone within a certain range. At 14th level, maybe you can grant a full action to one character as a bonus action. Dunno, I'd have to let people who are far more mathy than me figure out the exact numbers here.
Stances could be bonus or full actions to activate, depending on how powerful you want them to be. Let the stances last for 1 minute. You can use a number of stances per day depending on your level.
Your base Warlord, like the base Barbarian would come with a handful of common abilities - ranged healing of some sort (I really do like the idea of allowing allies to spend Hit Dice in Combat with bonuses, plus maybe a bardlike bonus to all healing on short rests), a second attack per round, maybe a way to trade an attack for another character's attack or trade your move to move another character, some skill bonuses (I love the idea of granting bonuses similar to a Guidance Spell) to allies at 7th level and you're done.
I really don't see balance issues here. Sure, there could be if you're granting too many actions or too high of a bonus, but, none of this is inherently unbalanced. I'd also point out that all of this exists in other classes. Nothing is particularly new here, just combined in a new way.