I don't get why people are acting this way over a character being added to the game. Last time I checked, this is a game. Is it not? What's the big deal if we get historical characters like Abe Lincoln or dead characters like Bleeding Gums Murphy.
The important thing is we're getting newly added content very consistently. That's the important thing. As long as the character has shown up in the series, then why not. It's not like they're adding Peter Grifith, Chewbacca, Green Lantern or Cartman from South Park.
Also remember its a game for a fictional animated family. It's not like we're playing a game based on real life events.