Colour me unsurprised. It's WotC all over again. Outreach to fans of previous editions.
Well, there's a difference between Andy Collins (a 3e WotC guy) or Ari Marmell (a d20 freelancer) rewriting Tomb of Horrors for 4th edition, and WotC asking Gary Gygax to write it (which they didn't).
At least FFG went back to one of the original authors, Graeme Davis, who's going to be co-writing and/or developing it. He says more about it on his blog,
http://graemedavis.wordpress.com/2012/03/01/the-enemy-within-again/where he clarifies inter alia that it's not going to be a conversion at all. Think Return to the Temple of Elemental Evil, and I think you get an idea of where they are going with this.
That apart, I'm frankly amazed at the sort of hate and doomsaying this announcement draws. Because they go the route of 'Return to the Temple' it's writing on the wall that Warhammer 3rd is dead? Geez - did you say that too when Monte wrote something similar for 3.0? No? So what's the reasoning here? Another bout of wishful thinking?
I have no idea.
As for myself, I've just been in touch with our Deathwatch GM earlier today and we're going to run this campaign later this year. While I don't have high hopes, I look forward to it, and I'll certainly post play experience with it on this board.