Its doable to get doc at 31. All it took me was a little bit of patience and ingenuity. I also only used kira until I got doc, I always made sure her gear was on par or better than mine.
I gave kira a dark side 2 lightsaber that I got from the vendor on tattooine, she cant use any li ghtside items. Im going to assume that your companions dark/light alignment is the same as whatever yours currently is.
One thing I will say, I specced combat until 29, I told myself everyone was just bad and had no idea what they were talking about. On a whim I decided to switch to watchman when I hit 30, wow it made a huge difference. Mobs seem a lot easier and the way I know for sure that it is better, I went from averaging 60-75k damage in a warzone to doing well over 100k (most games Im at about 145k).
For reference Im level 33 currently.