I recently had an arrival into AUH which was all nuts in early morning - basically we had to wait in the bus since the stairs upstairs were all blocked with people. Nothing moved basically. Luckily I knew there is an elevator on the left side that brought me relatively close to the security area (where I, as a pax in C, could take the fast lane which took only like 15min..) - I would expect Y pax to have waited for at least 90min in total, if not more. Certainly plenty of missconnects there.
Arriving into AUH/departing from AUH, it can also be quite chaotic. I certainly don't like the transfer/arrival/departure facilitities too much. Plus, mostly bus gates after all.. if you're for a smooth transfer, I'd avoid AUH. As much as EY in the air is good, it's the worst **** on earth on the ground..