So far, the single biggest mistake Bioware has made is their default chat filters. It's a simple mistake, but I think it has surprising large ramifications.
Now, this is a hobbyhorse of mine, so maybe I'm overstating the impact. Especially since every recent MMO has made the same mistake, in my view. Heck, maybe it's a sign that I'm wrong.
By default, system messages are sent to the general chat box. And there are a ton of system messages. When you hit level 25 and unlock your Legacy (shared XP pool and last name between your characters on a server), you start getting a Legacy XP message every time you earn normal XP. That's two lines in your chat box for every XP event. Which is every time you kill a mob. And the default pull is pack of three to four mobs.
Basically, the spam of system chat messages makes your chat box useless for its primary purpose. SWTOR is an extraordinarily quiet game, which is surprising for such a new game, and one that gets quieter as you increase in levels. This is very unfortunate, because you need the chat to organize groups to take on the heroics.
Go into the game, and turn off system messages in the general tab of your chat box. Turn it on in the Other tab (may actually happen automatically). All of a sudden, the general chat becomes usable once again, and you still have the Other tab if you need to recall a system message.
Of all the changes Bioware could make in their next patch, I strongly urge them to turn off system messages in the default chat box. I think it would make a world of a difference community-wise.