Mosley's handspeed and power will make Pea very wary early on....until he figures him out in the middle rounds and thoroughly outclasses him. This would be a great fight at 135...at 147, it might be closer.
Whitaker would just be too much imo, too much of everything. The lightweight Mosley was a dynamo and would be soon realsiing that tremendous ring craft in absolutely every aspect of the term neutralises and stunts his explosive onslaughts. I don't see how Whitaker doesn't tame him over the distance.
In theory this would be a really good fight.... but Mosley might just quit mentally as he did against Wright and lose a lopsided decision, in which most of the rounds in the 2nd half of the fight are very easy to score. I'd like to think it'd be a belter, one in which we see the best of both, but I've got my reservations.
I don't even think Mosley looks as good as him though, he is an explosive dynamo at 135 but he was an improved fighter at 147 imo for sure. I don't even think it's a great fight in theory, I see it being maybe very good early on but as it progresses I don't see anything but a taming tbh.