TR:U as in Tomb Raider: Underworld...? Oh christ... That means we can look forward to lush cartoon style levels with some of the worst ever character models coupled with a really bad colision system and clipping issues and an insane shitty camera...
I hope Thief 4 uses UE3 tbh. Theif 3 looked, and still does look, stunning. That was on UE2. So its not like they would have to re-leard EVERYTHING. Thief 3 was already quite ahead for its time with how they created assets for the game.
As for Dues Ex... I just dont know. After what they did with 2, I just don't know... I got the game free with my GPU and still cant bring myself to play for long periods, its just... Dull...