I think offline mode sounds like its lacking...something. Maybe because the past few months I've been reading and watching so much about Smash brothers Brawl, Its kind of a shock to see the same company bring out a game with so little in the ways of extras other then a few secret characters...something that’s not really new to the series.
However after reading the Iwata asks thing, I think online mode is going to be brilliant. I'm really surprised Brawl didn’t get the same sort of options for its WiFi mode.
I have to say though, if this didn’t have online play at all I probably wouldn’t buy it until later in the year second hand.