I think the Vault of glass is longer with more than 1 encounter per area. Plus, in my opinion Crotas End was way too short. Plus, I believe the longer the better. Not longer from dying over and over and over again, but just more content. From the previews, they said Raids weren't meant to be done in one sitting, yet people do 3 or more raids in one sitting. I'd like longer raids because they become more engrossing and have some potential to drive story as well.