Man that would have to suck when your training and your getting your ass whooped by your 55 year old trainer.... I think you are absolutely correct though, considering how he keeps himself in shape .. he'd not be world class but still great experience to spar with in his 50s.
I think he would be a great trainer. A lot of people see Hopkins as a moron for his antics but everything he does is clearly calculated and thought out. He would be a good trainer because he sees things that most don't. Hopkins isn't the most talented athlete but he uses what he has very well. He has a very good boxing mind and it helps that he didn't get punched too many times in the head, so he won't be stuttering in the corner.