I was thinking about this and unless they really really really reduced the number of trash mobs in instances I don't see how you are going to complete an instance in ~14mins. 17 runs of an instance isn't that bad. Ya gotta think that you will learn new things that will make it easier and easier every time. Running some 50+ times will get you pretty familiar with the instance and should be a good instance to run on heroic if you get all the tricks down.

As far as times I am thinking it might take double what they say. As far as the last boss in Utgade Keep not sure if he is going to be doable.Maybe staggering earth elementals in the 2nd phase of him will be the trick. But I don't know how any team is going to survive at 20k aoe effect.