Yeah, I can see where you're coming from. With only WoL (being worth 2-3 playthroughs most), classic mode, and the other modes (still haven't tried them), it does look lacking. It feels weird not having break the targets or homerun contest, but I don't think I played them aside from doing challenges. It's likely most people never really played these extra modes, so that may be why they were removed from the game. They were nice extras but I'm certain most people buy the series for the multiplayer fun. I do wish there was a Melee style adventure mode though.
Also, if the spirits did have their usual extra info on them, I wouldn't mind the switch to essentially stickers. But the text is missing, and that's a real bummer. I would have loved to learn more about the more obscure spirits.