Personally, the story mode and cut scenes are a waste of time. Just give me a more expanded multiplayer. That's the gamemode that lasts. Also, give me a real online mode, with leaderboards, stats, ranks, etc. Give me the ability to make my own rooms with adjusted item rulesets.
Cut scenes... meh. You watch them once and then never again. Story mode is something you play to unlock characters and that's pretty much it. I wish they'd spend 100% of their time on multiplayer mode, characters, and stages.