I don't notice much change. A year ago there were still flamebait threads, spamming threads, interesting threads, excellent threads and everything there's now. Some people have left forever, some people barely come anymore, but there are new people, some that started posting less than a year ago, and not for that they aren't cool people.
I mean, yeah, I miss some people, some posters that have left were funny, but that doesn't mean that some new that have come aren't as good, or that the quality of discussion isn't as good as before. Of course, you can always give an example of "man, this thread sucks", that has always happened and always will, you can't expect in a 50k community everyone to behave well, it always happens. What matters is that the community isn't getting any worse, nor is the content of the threads