voodoo47: I was under the impression that as long as you require the original datafiles to run your remake/mod/port, you should be safe -
Gydion: Yes, that's my understanding as well. I think it's more that they have no interest in recreating the original campaigns, as you said, and it's just an additional excuse to use. The Thief 4 release may have them be especially cautious as well.
Gydion, it not about looking for excuses or being lazy, but more about taking unnecessary risks with regard to copyright issues. See, if you look at what happened to the many Halo mods, to the Battlestar Galactica mod for Nexus, as well as MechWarrior: Living Legends, then you surely will understand why it is absolutely out of the question that the team ever touches copyrighted material from Thief. Believe me, with the success of The Dark Mod and the lack of success for Thi4f, Eidos/Square Enix would love to put an end to TDM.
That being said, you can always start recreating the original missions in the TDM engine, provided you don't post the files in their forums. Maybe TTLG.com would be the place to go, but since those goons frown at TDM for existing at all (and therefore "polluting" the memory of T1/2), I have no high hopes for that.