Remathilis
Legend
Personally I think there is too much focus on healing and attack granting.
It think the warlord should focus on the warlords' other feature: Commanding Presence.
Essentially, it would work like Bardic inspiration or the MM's Leadership action.
It would be the warlord's signature thing.
That might be a decent way to handle it. A warlord gets a beefed up bardic inspiration dice, but can cash them out for some battlemaster-like maneuvers, which includes burning a die to grant an extra action, give temp HP, or use a HD in combat. On their own, a die grants a bonus to a d20 roll. Powers can level or have min warlord levels to take.
All you need then is a few ribbons and minor abilities.
As for subclasses:
Marshal: "default" subclass, focused on war/battlefield stuff.
Captain: sailor/dread pirate variety adept at the sea.
Aristocrat: "noble" who has diplomatic skills and social prowess.