How strong is a 2072 Rear Axle Assembly?
 

I am considering swapping one into a 5252 ***IF*** it is strong enough to hold up.

That would be an interesting swap. It might work. As long as you stay in the limits of the 2072, you should be ok. There are axle braces that you can install to make it stronger. You might have to modify the frame rails. The 5252 frame rails are spread out.