Soundwave on 13 August 2009
The thing is I don't think the more "cartoony" style for Mario really is what the masses want.
Yoshi's Island was very inventive visually, but the masses overwhelmingly chose Donkey Kong Country, which wasn't as cartoony/much CGI-ish. The more cartoony Mario gets, I think the more it seems to turn some people off.
The design choice of NSMB recalls the original Super Mario Bros., which was pretty simple, and for better or worse I think there are a lot of people that like that style. Look at something like Wario Land Shake! -- great animation, great sprite work yes ... but it's not going to sell anywhere close to NSMB or NSMB Wii.
