EzekielRaiden
Follower of the Way
The main idea I had for a Warlord was to steal the overall structure of the Warlock, but repurpose it.Warlord - A combatant that leads through force of will and leadership.
Invocations become Tactics, always-on features or modifications of your other abilities.
Patron becomes Presence, which defines your Leadership Modifier (Cha = Bravura, Wis = Resourceful, Int = Tactical) and your overall approach to coordinating your allies (Bravura is high-risk/high-reward, Resourceful has the most pure support, Tactical leverages specific ally strengths).
Pact becomes your Leadership Method, whether you're a Vanguard (melee with stronger defenses), Skirmisher (ranged with more mobility), Prowler (stealth and precision strikes), Overseer ("lazylord"--working more through others than personal effort), or Magister (combining magic with battlefield coordination).
Spells are replaced with Strategies fuelled by a Gambit resource, which should flow freely during both your turn and others' turns--you care about what happens to the people on the team. E.g. Bravura Presence might give you gambit when your allies land critical hits, and Vanguard Style might give you gambit when things attack you. You can only have so many prepared strategies at any given time, but can change things up on a short rest.
I haven't come up with a good option for replacing Eldritch Arcana yet--but then again, I haven't done more than idly considering the above ideas. But I really think it could work quite well. By having different Presences and Methods, it's possible to capture many of the different flavors a Warlord could take without needing each Warlord to be bringing every focus to the table. And it would be a nod to the more option-filled character building that many 4th edition (and even 3rd edition!) fans enjoyed and can't always find in 5e.