Mannahnin
Scion of Murgen (He/Him)
class subclass structure is just another way of doing Prestige classes. Not really innovation. Warlord base class was just a fighter subclass so borderline innovation. I think nothing since 3rd has truly had innovation. Most changes have just been change for change sake so we can print new books. I suppose you could call magic item attunement an innovative thing but whether it made the game better or not is arguable. I can't think of anything innovative in 4e other than trying to make it easier for the DM.
- The healing system being proportional to each character and limited by a per-character resource (surges), so for the first time non-combat classes like mages didn't recover from injury faster than combat classes like fighters.
- Non-AC defenses being reversed from traditional saving throws, which also allows for critical hits on them.
- The entire AEDU power structure changes how the classes function and unifies the attrition over an encounter or day better, resulting in the closest D&D has ever been to caster and non-caster classes feeling balanced with one another.

I think calling Warlord "just a fighter subclass" is unsupportable. No Fighter was ever a primary healer (Paladins had miniscule ability compared to even a first level AD&D Cleric), and no Fighter gave force multiplier bonuses to the party, or free actions to fellow party members. I suppose if you want to cite the Marshal from The Complete Miniatures Handbook you could source the concept partially to 3.5, but it wasn't nearly as developed a concept and I didn't really hear of folks using the class.