Star Trek Online looks like a great game. But I can't see my way clear to cramming in another MMO right now. I'm already splitting my time between Age of Conan (impressions coming soon) and Lord of the Rings Online. And then there is Champions Online, which I have yet to crack 15 in.
I'm also not too eager to risk falling in love with one game before launch and having it become another right after launch. I'd rather wait a week or two for the dust to settle around whatever last minute changes Cryptic feels the urge to make, and then try the game from there. I never experienced the defense nerf (hey...that sounds familiar) that Champions Online got on launch day, they had adjusted things back to sane levels by the time I got my PC up and running again. However, I don't think I would have enjoyed it.