The thing with Pacquiao is that he's been knocked out, but he's never been TKO'd. I've never seen him get hurt, then beat on until a stoppage. I think he probably recovers from a punch as well as anybody in his weight class.
I mention that because what you said is true, it would get very interesting if Danny connects. What would happen if he dazes him badly? Would Pacquiao run? Hold? Or stand and trade? I've seen dozens of Pacquiao fights and I've never really seen him hurt badly in the ring (except for the knockouts). He had a rough fight with Morales, and was hurt by body shots with Margarito, but never anything like what we saw with Khan against Garcia, where he's holding on for dear life.