i have a good feeling that geno will be in brawl. hes only appeared on nintendo platforms and nothing else (i kno hes only been in one game, but i forget if hes been part of something like an easter egg or a cameo in another), which makes him a unique third party character, one thats closer to nintendo than all others. square is closer than ever to nintendo, and if i had to guess any of their characters to make it, it would be mallow, geno, or black mage. black mage is a lil too generic, and geno has appeared on the poll, and is far more requested than many other characters.
other than that, i think he fits well in brawl. his attacks could work nice, heres a moveset i was thinking:
B: Star Gun - Charge it up a little (can't hold a charge), and some stars fly out to hit you opponents. The longer you charge it, the more stars fly out faster and with longer range.
B Smash: Geno Whirl - Obviously it won't have the effect to do 999 damage, but he would essentially throw out a disc super fast. For it being such a fast attack, it won't do too much damage, and Geno would probably take some good stun afterwards.
B Up: Geno Boost - Ok so it's not the same effect as it was in the game, but the name somewhat fits. Think of it pretty much as a third jump. Perhaps just a cloud of smoke appears where he was and he just propels himself up. It would definitely help a lot, but not as good as many characters B Ups. Maybe he could have gliding with his cape or something? lol
B Down: Geno Blast - If I'm not mistaken (I haven't played Mario RPG for like 2 years), this is the one where a colored beam of light shoots down with a small blast at the bottom. In the game he summons a bunch of these, but in smash he could just summon one down that appears in front of him (not on him), and it works like Pikachu's Thunder attack. It could be a random color whenever you do it.
Final Smash: Geno Flash - 'Nuff said.