I don't recall exactly when I quit, maybe 6 months ago? I have a level 45-ish Sith Inquisitor.
I was frustrated with finding groups. The lack of dual spec, the lack of a LFG tool, and the fact only two DPS could be in a group made it impossible to find groups as DPS (it was very difficult as a healer as well - at least, at lower levels).
What put me over the edge was, after sitting around for an hour in fleet LFG one night - frustrating enough as it is - I was killed by some sort of debuff that was part of an event that was going on. "Feverish" I think it was.
Have they implemented dual spec, LFG tool, or made groups able to have more than 2 dps? Failing that, is there anything else that will make coming back worthwhile?
I do miss leveling in the outdoor zones, I thought they were great looking. That's most of the itch I have to come back, tbh.