I think there's an issue with the Warlord as I hinted at earlier in the thread in that it covers a whole lot of things - some of which are easier to implement in 5e than others.
The 4E warlord could
- give up attacks to make others attack (lazylord when taken to extremes)
- provide static buffs to other classes (in 5E this would be done by having effects such as bless granting advantage or something like a Paladin's aura).
- Healing (difficult to implement in 5E due to the different ways healing works without it being explicitly magical) - there are things you can do - eg temp hps and the like - but they probably wouldn't add up to the abilities of the 4E warlord in this area. (i.e no "Stand the Fallen Daily when you rouse your unconcious allies heal the whole party and yell "Once more into the breach".)
- Act as Force multiplier - abilities to make an attack and then grant an ability to others to make an attack. Or charge and others charge to - or attack and then move an ally - or push a guy and then every ally that's adjacent gets an attack. This is easily done in 5E - The Battlemaster can already spend short rest resource to make an attack with a reaction - it wouldn't break anything in particular to grant others an attack on their reaction. (This is the one thing that - except for the one Purple Dragon Knight tenth level feature is completely lacking in 5E.
- Grant movement to allies, shift the game boards around etc (easily doable in 5E as the Battlemaster has a limited version of this and the glamour bard has a major version).
You can easily make a subclass that does some of the above things - there's probably not a subclass with enough scope to
all of those things.
Rob Schwalbe's Warlord class (which as I always point out in this thread already exists - and is written by one of 5E's designers), covers most of the above points - it has attack granting from level 2 (so no beginning as a lazy lord) it has buffs and buffs, it has some movement granting abilities - although mostly in the capacity of extra movement. What it doesn't do - which is what I personally enjoyed most about the 4E warlord is allow the big of turn "I attack and then you attack" options or the off turn moves and combo set-ups. (But it's difficult to really pull of this sort of combo without the inclusion of an equivalent of daily powers).