Well I think that there are some good changes that the CU brought, and some not-so-good changes. Some examples of good changes: multi-passenger speeders, grouping is now a lot more effective, in some ways combat is more realistic (you aren't as powerful as a god anymore. I was TKM before CU, and even though I was really strong, it did seem a bit to unrealistic), inspiration buffs (+10% xp for up to 3 hours. You get them from entertainers), it's a lot easier for new people to get going and into the game now (with grouping), and some other minor changes that helped things out.
The CU brought some annoying changes, too, though. For example: Soloing is no longer an option, so if nobody wants to group with you, you are at a loss; colored icons (dang, I think they might bother me more than anything else in the CU. The regular white/blue ones were cool), stupid/annoying combat annimations (for some of the special moves, and things like stunned and bleeding), and some other minor deals that irritate you every once in a while.
I think that the biggest issue was change. SWG is still fun, and I don't plan on quitting, but it doesn't feel the same as it did. As stupid as it sounds, I am feeling nastolgic for the old SWG. I would not say that the CU is "bad", it just takes a lot of getting used to.
I don't know about the other galaxies, but Shadowfire's population has been AT LEAST decreased by half. I think it might be more like 60%. It really bothers me, too. somewhere near 10% of the population are Jedi, it seems, as opposed to where it used to be, which was around half a percent. I think that the die-hard players (like myself) kept playing, as did the Jedi. The less die-hard players quit, (on Shadowfire, anyway), so we are left with the die-hards, the Jedi, and the new people that have come in post-CU. I think that some people should transfer their Characters to Shadowfire, we need more people. That would make ME happy.... lol. Anyway, take care. If anyone joins Shadowfire, let me know, I'll give you some kind of appreciation gift (might be just a pat on the head, though...) Take care.