giving them the commander's strike maneuvre as well as aura effects like the paladin and perhaps something comparible to bardic inspiration are definitely things a warlord should have, i'm going to list a few other things i've seen around in 5e's mechanics that i think ought to be the basis of something thrown into their mix. (some of these might not be word for word RAW but you get their intent)
hobgoblin's Fey Gift: this allows you to take the help action as a bonus action with one of three specific variants hospitality, passage and spite which each respectively give both of you 1d6+PB temp hit points, increase both your walking speeds by 10ft until your next turn and the next enemy the helped creature hits has disadvantage on the next attack it makes.
tandem tactician feat: lets you take the help action at 10ft range to assist up to two allies making an attack against the same creature.
inspiring leader feat: lets you perform a speech before a battle that gives allies temp hit points.
interception/protection fighting styles: lets you use your reaction to reduce the damage dealt by an attack/impose disadvantage on an attack roll made against an ally within 5ft.
providing a higher than average or AoE flanking bonus is something i could see them with.
i know people don't want a warlord with magic and i honestly agree but if it really came down to it i'd rather one with magic based healing than one that can't heal at all, healing word, cure wounds and their mass variants, healing spirit, some other support like bane/bless, shield of faith, aid, warding bond and suchlike.