infielddad,
Your analysis and stats are quite sobering. They are consistent with what I've heard all along, and yes, there certainly are a number of contributing factors to the degree of recovery.
I remember the first stat I saw for "power pitchers" recovering fully from labrum surgery (I can't recall the source, only my reaction to the stat), was less than 5%. Talk about taking the wind out of your sails! Further investigation showed more promising statistics, more in line with what you've outlined.
My personal experience with orthopedic surgeons, was that most times they would hedge on recovery (a shoulder twice and a knee twice, both years ago). I was heartened by the surgeons prognosis for sons recovery, although, the reason, as you state, may be attributed to a change in the way doctors approach prognosis these days...from a more positive angle rather than the former negative, CYA angle.
For the record, the surgeon considered Juniors tears to be minor. One requiring one stud, and one requiring one stud and one stitch. I'm sure to some degree, this is a factor in his recovery.
Thanks for both your well wishes and your sharing. I know you have been down this path and your experiences and perspective are invaluable.