I agree that T4 can be a nightmare, I have had to wait 20 minutes myself and it seems to be getting worse. T1 doesn't seem as bad but still worse than it used to be. Often there is no queue at the non-EU desk while the EU queue is huge. I have tried using the non-EU queue in desperation before but was sent packing!.

Maybe they should introduce something similar to what they have at AMS and many other airports (ARN and CPH are another two) where there is an EU only passport counter and the other counter is "any passport". If you get to the desks and there is no queue (or significantly smaller) then you can jump in the other queue.