Substitute for Prince Diablo Mid
I had similar experience with the Diablo Mid. Loved the control but the racket killed my elbow. I strung as low as 42lbs with prince synthetic gut. It still hurt. Natural gut helped somehow.
The one racket I think is very similar in play to the Diablo Mid is the Gamma 340X. Has a little more flex and is quite a bit more comfortable though not quite as precise as the Diablo. Plays well with natural gut also.