I have, just not as much as I used too.
Personally I'm a little tired of testing when it's only a few that are getting their voices heard. Lots of bugs are reported, like the growing problem of getting stuck on small objects (in the retail game), but nothing was ever said or done about it before Final Stand came out. There's a new collision physics that they put in CTE that they want to bring to retail, but other then things being said about it for about 2 weeks (from DICE), nothing else has been said and I assume nothing changed. From the little that was said from those on CTE, it's much easier to get out of the map now. Should make Metro fun again.
CTE seems to be turning in to an area to test and work on new features on a massive scale, not necessarily fix bugs. While the features are nice, they also bring with them new bugs. We're getting back to DICE adding features at the expense of fixing the problems that keep reoccurring from BF title to title (i.e. your TV missile hitting your helo still is not fixed). Also there's a guy on Symthic that helps one of the DICE guys on gun balancing. So community is not really a description of who DICE wants to hear from and want's help from, it (seems) but a marketing ploy to get you to give them some in game statistic feedback on changes, not necessarily what you think about said changes.
Things like the play test are nice because you can see how a bug that causes vehicle wreaks not to disappear causes lag and weird stuff happening in the server. The kind of stuff that is often associated with bad netcode. Shouldn't that be more important than trying to figure out how to give us night maps? I'm not saying that it wouldn't be nice, but I'm not interested in helping them test what would be nice. When CTE started, the idea was to help DICE fix the game, not test out new features when the bug list becomes "acceptable". During the summer DICE was asked for help on server degradation issues and at one point one of the patch notes said that they think they had it figured out what was causing it, but nothing else (that I know of) has been said since last summer. I pretty sure there was never a server patch with said notes so I can only assume that they still have not fixed the problem in the last 6 months.
I was one of the few that got in from the US when CTE opened up initially. While yes it did suck only being able to play on a Europe server since that's most of the people who got in, it was also true that DICE listened a lot more (obviously since the initial group was so small. I think only 10k sign ups were open initially). There were a lot of cries to open CTE up again at that time. I was very much against it. The player quality level was very, very high and there was a lot of talking that would go on in the chat about bugs and being able to reproduce them. The forum was also very productive in being able to get comments from DICE. It was not too bad until they opened the floor gates wide for Final Stand testing. Since the initial Final Stand test, things seemed to have gone off the deep end with respect to getting any one from DICE to mention any thing in any thread unless the thread has comments in it from certain people in the community. If they have a positive comment to it, I can guarantee that a DICE employee will soon be leaving a comment in the same thread.