It looks like connectivity will be key to these games.
The key to Smash Bros. on the Wii U and 3DS will be dual support, Masahiro Sakurai told IGN in an interview.
Sakurai said "There is a certain dead end we come to if we just expand the volume of the game. I intend to change direction a little as we go. The key to that's going to be its dual support for 3DS/Wii U. I'm really just getting started on this so it's going to take time, but I'll come up with something that uses that link as the game's central axis, so I hope you're looking forward to it."
The simple addition of new characters does not appear like it will cut it for Sakurai this time around. He plans on focusing on connectivity between the 3DS and Wii U throughout development.
Super Smash Bros. was originally announced last year at E3 for both the Wii U and 3DS. However, due to his work on Kid Icarus: Uprising, Sakurai was unable to devote time to Smash Bros. development. With Kid Icarus's recent release, it appears Smash Bros. is now getting his full attention.