"Would you rather have the union mandated senior Fright Attendants, or like the bankrupt airline in Mexico: reach age 26 and fired?
In this case, I don't see how it would have mattered one bit of there were no CC at all. The plane was ditched on the Hudson river and it was sinking. At this point it should occur as a good idea, to even the densest of passengers, to get the hell out and as a secondary objective: grabbing a floatation devide on the way. They even had plenty of time (relatively speaking), thanks to excellent piloting, a well designed aircraft and of course the many ferries that combined for a tripple whammy saving the day. The CC role appears largely irrelevant thus far.
I would however expect the CC to rehash the RELEVANT parts of the safety briefing, as it became clear they were landing on water, even I would pay attention at that point. This should include brace technique, floatation devices and procedure for doors and evacuation. If the passengers don't listen at this point, just imagine how utterly useless the pre-flight briefing really is (in terms of actual safety that is, psychology and establishing an authoritive cabin leader has obvious benefits.) I believe one of the passenger accounts included that water was leaking in quite early in the back and "they" (don't know who) tried to open the aft doors without much success. Some posts here indicate those doors are best left closed on a ditching, so it may appear, to my untrained eye, as if everything didn't go 100% by the book on the evacuation?