Bit late to be changing style drastically, especially after 5 years out and blowing up in weight. Also very short for 160, what is he? 5'7 - 5'8? Nope.
He was never elite to begin with. He went life and death with Ortiz and got hurt bad by Khan. He would get it worse than josesito Lopez did vs Canelo.
Maidana is finished at any weight. I think a comeback would be a mistake. He was a great fighter to watch in his prime.
Maidana under Robert Garcia's training went from a C fighter to a A- fighter. The Maidana that lost to Ortiz/Khan/Alexander is not the same that beat Broner and had a close fight with Mayweather. To answer the topic, I think Maidana could beat at least one top 10 fighter at 160, not sure if he would beat a title holder tho.
If he was matched with guys who can't punch he'd be alright and lose decisions , anyone in the top 10 would brutalize him.