The shop that did the gear install is experienced. Nobody is beyond making a mistake but if I was their mistake let's just say that was some pretty crap luck.
A friend of mine has a 8.8 with a 3.27 gearset and his has a lot less play in it than mine. Same test conditions with brake set and in neutral. Some or all of the difference could be due to my 4.10. I just don't have the experience to know.
I have had at least one person on another forum tell me his is just like mine. And seen posts from people who said up to 14 degrees of slop at the flange is fine. I just keep reading conflicting stuff. Makes it hard for a newb to decide on a course of action.
I appreciate the responses here. Guess I'll have to think this over a bit. Would be nice if I had another car to compare that had the same rear end and gearset to get an apples-apples.