I'm not totally sold on AJ yet,but I will admit he's got tons of potential. I think he will be a beast to deal with at 170 with his height/reach and his potential.
Thiago is right most fighters are getting bigger stronger,and taking better care of themselves. Guys like Hughes/Serra will be hard pressed to be competitive with guys like these.
If Hughes/Serra continue on I agree maybe a drop to 155 would be best for long term..Heck Hughes drops down beats a few guys beats BJ, Hughes would of held two titles in 2 different divisions.
Sadly though,Im sure hes gonna retire though he did say Karo owes him a fight...