Is Koei too lazy?
Well, 4 previous models upgrade to playable.
13 new models of which 4 (6 if count Shanks and CC) are confirmed playable. Make it 19 if Shanks, Rayleigh, and Coby showed up as support and not in cut scene (and CC, Vergo, and Monet).
A total of 36 playable (if including CC) plus 9 strawhats extra. People like Burgess and Bellamy are included due to relevant in multiple stages.
In the next game, even if Kidd is added, he probably will the the only new supernovas unless other show up post timeskipped and show more movesets.
Alabasta need improvement. Skypiea need a lot of improvement. Water 7, assassination of Iceburg should be include once we have Kalifa. Enies Lobby also need upgrade. Thriller need Absalom and Ryumma (DW games are only fun due to the vast amount of enemies and not just allies that is why it doesn't matter if Ryumma has the same moveset). Sabondy need upgrade depend on how many supernovas show up in the story a year or more from now. Impel down is pretty good but need more enemies generals (too many allies, not enough enemies). Marineford actually look pretty good (they probably would have add Hina but it hard to translate her moveset). I am pretty sure only Hody is in Fishman Island, he need more subordinates. Punk Hazard seemed pretty good. Though in the next installation Baby 5 and Buffalo may show up. Dressrosa need ton more improvement. Coliseum will be pretty hard to translate into the game. Unless it became you vs every body out and they only appear in group at a time and then show up more.
So this new game seemed like a pretty average upgrade by Koei (so not really lazy I guess), not bad but not that great either. But it hard to add everyone who lack movesets. Also postskipped and preskipped models are drastically different for people like Bellamy, Burgess, etc (which meant more work, hence I rather have Kalifa and more enemies than said Nightmare Luffy). Movesets are already somewhat update in this game. But if you want more movesets then Oda need to cover more stories and have more fights. You can't expect people like Crocodile to have new movesets if that is all he had shown in the manga.
Either way, they should wait at least 2 years before unleashing the next game. Even then, 1 or 2 newstages will not cut it. Maybe one next installment will sell just like that. But the next one after that need a ton of new game play features or people will just simply bore. Or even translate these beautiful models and stages into a game where he can explore and stuffs. Mixing elements of RPG with DW style with Naruto storm style. A mode like Star Ocean game play should be fun.