When melee was out, i didn't think that they'd make another smash bros. but then they did (a.k.a brawl). but there's only one thing. if you check the interview on ign sakuri states that he doesn't feel the need to make another smash because it would just be (more character, stages etc.) to add without any new things. well, i don't exactly remeber how he said it but look for yourselves.