I switched to the 2013 APD+ this fall after my Jr son went over to it as well and wow what a great stick......the arm issue I'm sorry to say is so overblown! I'm stringing VS mains and RPM or Lux 4g crosses at 60lbs and not one issue. My 15yrs old is using Alu Power Spin at 26kgs....nothing. Also soooooo many of the older folks I play with (45 yrs +) making the switch or did so as well again no one having issues with arm pain.
My opinion for what it's worth is all the younger folks I watch and see playing with he APD and trying to hit every shot as hard as they can with huge crazy spin is what causes arm issues. Yes it's a stiff stick and plugging in a stiff poly is not a perfect match for comfort but the stick itself not the issue.
I was EVER an APD fan in he past - I had used the PSLtd + for years and had just started using the Blade 98 18x20 in Sept - until then that was my fav stick.