The problem isn't finding a group, the problem is that you almost never randomly encounter other players in the actual world... It creates a feeling that it's a single player game.
Earlier today I went to kill an elite for an quest (I'm lvl 45), went to the place where the map said the elite should be and it wasn't there, my first reaction was "oh damn it's bugged", but then I understood that someone else had killed it, first time in 45 levels that happened to me, thats on the most populated EU server (nadd).
In an mmo I like to feel that I'm actually playing in a alternative world with lots of other ppl, I'm not doing that in swtor sadly.