This whole "DX: IW sucks" phenomenon is interesting to me. I don't think it sucks, and apparently neither do most of the professional reviewers out there. Half the charm of the first one is how radically different it was from other stuff, but there were lots of lame things about it too. People should really stop complaining.
And I am sure Thief 3 will be at least pretty good. It's a good thing if designers have to fit their games into the "limits" of the XBOX. It forces them to have some discipline and efficiency, rather than creating games with an endless array of controls, half of which you never use because it's too cumbersome.