Thurman have that capabilities it's just so happen that Pacquiao manage to bring him down from the early rounds of their fight but we have seen him fighting back though not enough to impress the judge and the fans, but if ever that they'll be able to push this possible fight, I agree that bookies will favor Thurman here, fan base maybe he will get that edge.
That was a very different Manny Pacquiao that is younger, faster, and has that quite devastating punch that could knock out even Ugas, but sadly because of his age, and likely having busy with political roles, all those focused on boxing could not be found in him anymore, for me if he still has those quite sharp punches he can beat Ugas but it is now Keith Thurman's turn and for me, I might take Keith Thurman winning here, he is been beloved by other fans of Pacquiao now that he also become very good friends with Pacquaio, because Manny Pacquiao is a loving fighter that be friended even his recent opponents,
I will also side with Keith Thurman if a bout against Ugas will happen soon, we cannot compare them when they faced Pacman because they both fought Pacman in different period of time and I also believe that if Ugas happens to fight Pacman before or after the Thurman fight then Ugas will be frankly defeated. As said above, when Ugas faced Pacman, the latter is not that focused in his traning and preparations anymore as he is currently a senator at that time while also preparing to run for president too.