Korppi on 09 June 2012
The Mario universe is already bloated with lame, useless characters as it is. Besides, it's not like anyone buys the games for Mario's searing wit or Luigi's charming personality. Though making Luigi and the other playable characters play just a little bit different from Mario would be a nice touch, I guess.
What they should focus on expanding is not the character roster, but the universe itself. (And by that I don't mean 'take the series into space'. Been there, done that.) Give us more of the Mushroom Kingdom to explore, not just the same ol' desert and snow worlds.
