Ah the joys of AWD ( or penalties ). This is a timely thread as I just lost one tire this morning.
Worked at one of the big chains selling tires for a few years. Theory on the "best" tires on the rear are due to weight transfer and bias. Most vehicles are front engine designs which puts more weight on the front, thus enhancing traction. The other theory is during braking, weight is transfered to the front wheels and unloads the rear.
From a blowout perspective I also would choose a rear tire, at least when driving a heavy vehicle or truck.
Maybe it's time to +1 my rims/tires?!? Got the excuse, just need to convice the home boss...