Weight classes exist for a reason. Walters knocks him out or wins on points if he sticks to the jab and Rigo plays it safe.
I don't think beating Donaire at this point in his career means you're ready for that level of skill. Of course, he's got the size and power advantage, and he certainly is skilled, but I can't say without assessment that he can do it
Rigo counters him all night, rigo is a little speedy mofo with good foot work. N.W. is too flat footed to be effective against rigo.
Walters also has a seven inch reach advantage. Rigo's going to have to go outside his comfort zone to get past that jab and put himself in harm's way much more than he likes to score ebough to beat the Axe Man. He's the more skilled operator of the two, but that wouldn't save him in this case IMO.
Axe knows how to use that jab and that is the key. Rigo won't be landing any sneaky left hands because he'll be too busy eating jabs.
With that reach advantage and power surplus I'd favor Walters anytime. People seem to forget that Donaire, although outboxed, could still hurt and even drop Rigo. I can't see how Rigo would be able to outbox Walters like that who can pick Rigo off from the outside and probably even hits harder as Donaire. It's an intriguing matchup because of Rigo's skill, but I clearly favor Walters and by stoppage.