To Tonyc's point, the chances of a couple of key players getting in foul trouble is certainly possible. It has come close to happening a couple of times already, against teams less skilled than ND. And ND, you all remember, is better than most at driving inside and flopping to produce fouls. Yes, UConn players are consistently better conditioned than most and yes, all their starters are prepared to play a full 40 minutes in a semifinal or final game, but IMHO all the minutes logged in the course of a year COULD have an effect on their ability to go at 100% for a whole game. Against most teams, UConn's 80% is better than their 100%, but if you add foul trouble to the equation, things could get problematic pretty quickly.
Joe Pgh's observation that with a short bench you cannot press as much as you'd like is something I'd not thought about, but seems right. Fewer players means fewer coaching options. With a team as strong and well-coached as UConn, it won't matter most of the time. I'm keeping my fingers crossed.