I probably sound like a broken record with this, but...
Boshi from SMRPG absolutely needs to come back. Sure, this can be said about Geno, Mallow, and all the other characters from the game, but I think Boshi stands out...And since this is the Wario forums i'd think this character would be especially relevant amongst the characters from that game, seeing as how he is Wario/Waluigi version of Yoshi. His name in Japan is, in fact,
Washi.
I understand the reason why we don't see most of the interesting characters from that game is because Square owns the rights to them, but Boshi is a Yoshi, and Yoshi of course belongs to Nintendo. Shouldn't he be ok?
I agree with
@Magma on his stance of not wanting a bunch of "bad" versions of characters (thank fuck Miyamoto shut down that "Wapichi" garbage Camelot suggested) but Boshi I think is an exception. He looks cool, he debuted in a legendary game, and the idea of Wario riding around on a steed that's just as much of an asshole as he is, is awesome to me.