For diversity, I've said it before;
Tyroc, Invisible Jacques, Karate Kid 2 (Myg), Kid Quantum 2, GEAR, Dragonmage, Dragonwing, Harmonia Li, Chemical Kid, Glorith.
Five black Legionnaires, five Asian Legionnaires. (And there may be more that I don't even count, like Otaku and Mwindaji.) All surgically excised from this Legion by Bendis, in favor of race-changing pre-existing white characters.
The Legion can be written successfully with a large cast, set in the future, *BECAUSE IT HAS.* If this guy can't do it, that's not the fault of the property. It didn't suddenly stop being possible because a new writer entered the room.
I'll agree that it obviously ain't easy.