I guess for me Brawl is still a quality product, and I would be pleased to receive more of the same quality but with more quantity. Though, I'd like to think that Brawl provided a foundation (made of stepping stones? how does this metaphor work) to be improved upon this next time around. Y'know, better story mode, better stage builder, etc.
Anyway, since I hope Sm4sh won't suffer from long loading times like Brawl did, I really hope for a new "quick play" feature. Just press it and a match begins. Don't have to bother with results or select screens. You could adjust the rules elsewhere. I know you can already set up the rules to get essentially the same thing, but I DUNNO I DON'T WANNA GO THROUGH HOOPS GEEZ. Incidentally, I don't know where there hasn't been a "save rules" feature yet. C'mon, do I really have to change it to stock each time I turn on the game.