I wouldn't step into a boxing ring for the same reasons I don't think McGregor should. Most of his game won't be on the table, his strikes will be tempered, and he runs the risk of training himself out of his position in MMA. Whatever, though. If he wants to fight, let him.
He's a hard driver. He may stand a chance of coming out on top, but I wonder if his MMA performance will suffer as a result of all that boxing training. That's thing one that's kept me away from boxing. It's a completely different competition.
Of course, he's probably being paid well, and a feather in the cap of an MMA career would be taking out Mayweather in boxing. He could retire and feel pretty solid after that.
Cheers,
Kennith