The bird, perch, BG, and light quality are beautiful. Great work with the highlights. Just the slightest of head turns would take this up a notch as you mentioned. A little more DOF could have helped get a little more of the tail in focus. Beautiful work overall.
You are correct about the head angle, and I sortof wish the tail was behind the perch (and a nice perch it is), but other than that you did very well. Neat BG too with some interest-adding colour scheme.
Excellent use of flash, pleasant pose on an interesting perch, that irritating slight head turn would have made all the difference but nevertheless a fine shot.