Or combinations. Technically Meta Knight was a mode in Nightmare in Dreamland. Also, glad to see you liked the pic. He was in a fighting pose. Ideas:
CHARACTERS
Waddle Dee
Meta Knight
Gordo (Breaks any block, kills any enemy, maybe could be a secret power or something)
OTHER STUFF
Stages (I think Block Ball has a secret stage; I'd check it out if I could beat the damn Border Lines)
Time Attack (how many stages can you clear in 1, 3, or 5 minutes?)
Boss Rush
Just some thoughts.