Here is the warning from the Rubber Manufacturers of America on your question:
http://www.barrystiretech.com/16.5warning.gif
Seems like you have answered your own question about moving away from 16.5's.
I have them on my Jimmy because I got a screamin' deal on the wheels and the first set of big tires I had. The current 35 12.5 BFG AT's were also significantly cheaper than the 16" version. I don't put a lot of miles on it, so they will be out of service date long before tread wear an issue.
And I bought 5 wheels and tires. I made the mistake in the 80's with my Centerline Pro Truck wheels and NOT buying the 5th one.