It's probably about the same number of dice rolled as a bombing run, so I don't think it's the number of dice but the time it takes to do individual roll-offs. Overall it may add a few minutes to the game, but it's a trade off.
How does AC get used where you play? Here, AC is generally reserved for close range shotgun tactics, otherwise fighters take your AC down. Also, we heavily favor assault boats as they have proven themselves more useful to us time and time again. For us, this proposed mechanic would have us using assault boats the same way but we'd have a reasonable shot at using bombers at long range. This way we could have kind of a Midway type battle going on.
Aside for this mechanic adding a little bit of extra time, any opinions on what it does to the game?