PT is strongly overrated on this site. Do not get me wrong, he is a good young back, but he isn't a feature back. The only thing PT has ever done is perform against the worst, college defenses if you want to call it that.
Wells is a stud. He's 6'1, 240 and ran a 4.3 in the forty. I don't put much stock into the 40, but a 4.3 for someone his size is a miracle. Wells will be a star in this league, he has the speed and the power.
To be honest, I look at him as a better Deuce. Again, Wells will be a star. I'll say it, he will be AD good.
Lastly, your two needs. OLB, and FS. If Jenkins is on the board, you take him. No doubt about it. But who do you take at OLB? Matthews or Cushing? I don't think. What about safety? William Moore is a possibility. He should be a top 15 pick, if it wasn't for injuries his senior season.
If the top guys are gone, Curry, Brown, Orakpo, Jenkins, and others, and you can't find a GREAT trade back option, you take Wells.
I've said it before, and I will say it again. Payton likes to counter his pass game with a big power back. Wells fits that.