Repeat after me.
HARVEY SMITH ruined Deus Ex. Not Warren Spector. The worst thing that WS did was lie to his fans about what was going to be in Ex Deus : IW, he didn't design it. In the end, I think he just chose to spew good relations over his game, even though they were lies, because it was THEIR product. He could've hardly gone and said "Yeah, I think it sucks too, fuck Harvey Smith." right?
However, I don't really see what Warren can bring to Tomb Raider, as it's not the style of game he's been developing over the past 15 years. Unless he wants to add a lot more complexity to the basic formula.
I think Eidos just needs to wake up and accept the fact that Tombraider is a dead franchise. People have played 1, 2 - 5 games in it, and now they're bored with it. No franchise endures forever, and you can only do the same thing so many times before everyone just gets plain bored with it.
Tombraider is dead, Eidos. Move on.
Creston