I haven't had any issues whatsoever with my GF up to lev 25 so far, and I have the dog companion. Learn when to block and when to move, and learn your skills and you'll be fine. The class isn't bad; you are.
Everything the OP said, and might I suggest that you take another page from 4E's book and when the level cap goes up past sixty add in a few Epic Destiny progressions. Make them generic to specific roles, like Control/DPS/Healer/Tank etc. but not class-specific. Completely change the game post-60. Also, classes. 4E has a…