Our family is huge Phineas and Ferb fans. Every day. At least 2 episodes. Usually more. Today, I found myself watching it when my DD wasn't even home.
That being said, I sincerely hope they do not change the KP adventures. While KP is obviously bringing a 'cartoony' element to WS, I think it is a much better fit that Dr. Doofenshmirtz would be. And, believe it or not, you do learn some things about the countries/cultures while you are playing the KP games.
No, Kim is not on Disney Channel any more. Not even in reruns. About 4 months ago, they stopped showing it at 2-3am. We had been Tivo'ing it, because DD loved to watch it ever since she did the adventures.
I would love to see some P+F presence in the parks, but I don't think WS is the place for it. I would much rather see some kind of Phineas and Ferb "I know what we're going to do today" interactive game/activity in Innoventions.