What I don't understand is when a tank (or healer on occasion) joins an in progress instance of WP, doesn't know the party's limits yet, we wipe and then they quit right away. There is a 15min penalty for leaving if I recall, so leaving, waiting it out, and requeing again, then running the dungeon wil almost always end up slower than say another 20 mins in WP due to a lower geared group (or one that doesn't work well together). Even a run that takes another 30-40mins is still statistically faster. This is the same for most other 50 instances.

As a tank I have also noticed that most of the time I join an in progress group at 1/3 or 2/3 it takes longer to complete than if I went fresh. There is often a reason for a tank to leave mid instance (unless they elitist)