While Trailer Park does have lots of camping spots it also has a TON of spots to flank from. I had a fantastic round there the other day running around with the Vector, I mean run straight, turn left and you're behind 3 guys!
Carnival isn't as campy, I LOVE the setting and the map is laid out pretty well. Neither compare to Crash or Crossfire or anything, but they're solid!
I don't know man, people camp the hell out of the rocket area and the funhouse. It's pretty much Estate, minus the hills.
But I agree about Trailer Park. After learning the rhythm, I kind of like it now.
However, for the most part the new maps aren't good at all. Everytime I think they are okay, one of the older ones come up like Crash. And any of those classic maps trump anything else. I hope they do some more, but I doubt it. Activision has to protect the franchise. So as Black Ops gets closer, the likelyhood of new ones will drop.
I remember when they promised all sorts of playlists for CoD4, but it never happened. They had to protect WoW.