It's 5 right?
Yes every non title main event after ufc 138 is 5 rounds 
Shogun by Dec, Sadly
Dan doesn't gas? He faded badly against Franklin in 3 rounds, to the point many thought he should have lost the decision; he faded against Shields and Anderson and lost, he faded against Rampage and lost.
I've seen cardio be historically more of an issue for Dan than Shogun (other than the two fights in which Shogun was coming off surgeries and long layoffs -- and one of those fights Shogun won by finish).
Realistically, if this one doesn't end early it's going to turn into a slopfest. So fireworks or a bust of a main event, just my take on it.
Dr Dale Doback - Doesnt matter because the H bomb is getting dropped in round 1 on Shogun
if Hendo lands a clean shot, it will be lights out for Rua