I've been here since around August or so. I've seen some people come and go in the meantime (usually with a plethora of "DIS SUX IM LEAVING" threads). It's funny because you don't really notice it all that much until you go through your older posts and suddenly you're like, "Hey, I haven't seen that guy in a while..."
I have been here since June. A week or so after the announcement is when I found this forum section. This is my first post in awhile because, as someone else said, the posts get really redundant. People came and went a lot. I feel the forum had ups and downs. I see what you mean with some of the new guys being annoying about every noob post, but it has been like that for a LOONNNGGG while.
The trolls came and went especially after every announcement. I still remember the awful posts after the character leak... I feel this forum had one of its worst periods shortly after the release because of all the complaining. But it has cooled off significantly.