do you think the simpsons will add a new character?

I don't see theres any real need for them to, the current use of guess stars effictivly uses a new character (set of characters) in most epsiodes, allowing the stories to stay fresh without having to develop these characters / risk them going stale.

i think that they wouldn't add any more permanent characters to the show, because, as said previously, it would alienate the old audience. but they could try and phase in a new set of characters, gradually, not all of a sudden, like making them appear in minor roles, sort of like southpark phasing in the goth kids in. or, they could just go with their current formula of guest stars.

THat would be a bad move, because it would ruin decades of establishing their current formula. And it would be difficult to introduce a new character at this point because it would only alienate the long-time fans.