Normally a Level 20 ranger would have a CL of 16, but with This it would only be 12, I don't really get the point...
A level 20 ranger normally has a CL of 10. I don't know where you're getting 16. Practiced Spellcaster is a very good feat for a Mystic Ranger.
Sorry then, Didn't realize normal Ranger CL progression was equal to half his ranger level, I assumed It had normal progression starting at 4th.
Does Mystic Ranger not change CL progression for rangers at all then?