Should Andre be let back in to the UFC?
Yes he should be let back in the UFC. Since leaving he has gone 6 - 4. Not great, but he has shown that he is dedicated to the sport and has been trying to take the toughest fights available to him outside the UFC. And through much of that time been expressing that he is doing this to earn his way back to the UFC. The UFC should want a guy with that sort of passion and dedication. Furthermore, win or lose, his fights tend ot be exciting. He has wins over Roy Nelson and Ben Rothwell since leaving and his losses have been mostly against Good to great fighters.
How would he do against the top 10?
On a great night, he would be a thread to any top ten fighter. That being said, I don't think he is a top ten fighter himself. Probably Top 15 though.
How good do you think he was in the prime of his career?
I think he is in the Prime of his career. Maybe not in the prime of his career accomplishments, but I think AA today is better than AA in the UFC. I just don't think the the HW division was very stacked when he was in there. He has a tougher HW division to fight in the UFC now.
Do you think that the quality of heavyweights has just went up, or father time has passed him?
The quality of HW's has definitely improved. AA is still great. On a bad night someone catches him on his glass chin and he goes out. On a good night he has some of the fastest, hardest, most diverse striking of any HW and some of the best boxing and can make good fighters look totally outclassed.