"What is VERY important about the success of this game is that the famous "Capcom 5" is more likely to be GameCube exclusive. Capcom said in it's "exclusivity clarification" that they aren't guaranteed exclusives- it depends on the sales of them. Since this one sold well, the other games have a much better chance of being GC excusive. Very good indeed for Nintendo. I'm looking forward to Killer 7 myself..."
I don't think it works that way. Capcom recently announced PN3 would remain Gamecube exclusive after it sold so poorly in Japan.
Capcom cares more about its own profits than it does about Nintendo's stance in the console war. It doesn't have the attitude that it will punish the Gamecube by making a game multi-platform if it sells poorly or reward it by keeping it exclusive if it sells well.
Viewtiful Joe selling well probably makes it more likely to be multi-platform. PN3 won't go multi-platform because Capcom assumes that if the game didn't sell well on the GCN, it probably won't sell well on the PS2 either. So there's no point to porting it. But Capcom might look at Viewtiful Joe's sales on the Gamecube and decide, if it sold well on that console, it will certainly sell as well or even better on the PS2.
Regardless, this is good news for Nintendo. It will just make Capcom and other developers more willing to develope titles from the ground up on the Gamecube regardless of whether they eventually get ported to the PS2 or not.