Opening AT from EP is highly table dependent. If the table is passive and opps have a wide flatting range then it can be fine. But you need a plan postflop. What are you going to do when an Ace hits? Are you happy to see that on a wet board like [Ac 6h 5h] facing a raise or two floats?
Conversely, if the table is playing super tight then your hand is pretty much dead when a reg 3 bets you, especially from the blinds. So keep your range tight from UTG and your decisions will be nice. AQ+ from that position works well for 6 max