Huh. I can't help but think I started this whole discussion.
But Divine, even if Namco had the chance to have two characters, 3rd Party characters have to be a big deal. We saw this is Sonic, Snake, and Megaman. They are all huge characters and mascots of their respective companies. The next clear choice IS Pacman, and Pacman only. Lloyd is not as popular as any of these characters, and never will be. If there will be any more third parties, it will be Pacman, and that's it. No one has ever reached their level of greatness just yet.
Put it into perspective. Say there's a SEGA game, where it's all of SEGA's characters put in a Smash-like game. And, in the game, there is a Nintendo guest character. Instead of Mario, the one we all would think it would be, we get Kirby. That doesn't make sense. MARIO is the mascot, and the mascot only regardless of what anyone says.