Fans of Mega Man who have wished to see their favorite Blue Bomber engage in some fantastic fisticuffs have found themselves disappointed over the past few years. Sure, MegaMan Volnutt got to make his fighting game debut in last year's Tatsunoko vs. Capcom: Ultimate All-Stars, but when it came time for Marvel vs. Capcom 3's roster to be revealed, producer Ryota Niitsuma just didn't see a place for Blue, and that left a lot of fans seeing red-- and we don't just mean Zero. But before all that, players were left a bit steamed at no sign of any Mega Man in Nintendo's flagship fighting party game, Super Smash Bros. Brawl. With the likes of Solid Snake and Mario's longtime corporate rival Sonic the Hedgehog appearing (along with their own stages and other members of their respective casts), fans were certain that some form of the Blue Bomber would be a shoe-in.
But in the end? Nothing.
We would come to find out that Mega Man's exclusion seemed to be a comedy of errors, minus the happy resolution. Keiji Inafune would reveal that he was never approached by Nintendo to use him, whereas Sakurai would explain that they had not been approaching others; Hideo Kojima wanted Snake in Super Smash Bros. Melee, but his request came too late in development to be included, whereas Sonic wound up being the most-requested character in a poll they had conducted (one suspects that negotiation of the Mario & Sonic at the Olympic Games titles might have helped play a hand in that, as well).
Nonetheless, there are those who carry a torch for the idea of Mega Man fighting Mario, Link, and maybe Snake and Sonic, too. And it appears that there are even those within Capcom who hold similar desires.
The United Kingdom's Official Nintendo Magazine (not to be confused with Nintendo Power, despite all the key similarities) recently put the question to Street Fighter producer Yoshinori Ono, "if Nintendo had chosen to pick a Street Fighter character to appear in the big brawler, who should it have been?"
And interestingly enough, Ono's immediate reaction was not a Street Fighter at all:
Personally speaking, expanding the roster out to the whole Capcom, I'd really like to see Mega Man in Smash Bros because I think Mega Man really fits in that whole world. He has a high affinity with the Smash Bros. world.
So, at least Mega Man has one supporter in Capcom. With any luck, whenever Nintendo gets around to a new iteration of Smash Bros., he'll go to bat for the Blue Bomber, assuming Nintendo hasn't already taken the hint themselves.
But as for the original question?
"If I had to confine it to Street Fighter it would definitely be M. Bison because I would like that mega villain to fall upon those Nintendo characters and cause complete chaos. That would be fun."