As far as we know they haven't stolen engine code, level design, model design, gun balances, ai routines, huds, storyline etc etc. However a couple of tiny pictures...
You're right, but if they did in fact steal a few textures, that'd make me think (if I were id) I might want to take a closer look to see what else is in there that might be ripped off.
More then that - id has open-sourced their software for Doom/Quake1, 2, & 3 . . . but none of those licenses ever extended to the artwork and media files shipped with those games. Carmack commented on /. a while back that their open-source licenses have a provision that allow game developers to use their open-source code to develop a game, and if they want to release it commercially, can relicense it under a pretty cheap non GPL license.
The point being the id seems to be making great effort to allow other competitors to use their technology and source code to develop games - whether just for the community, or for consumers as well. But, that same permissiveness wasn't extended to their art assets. Stealing those things seems . . . well, frankly underhanded. They didn't give you enough?
The legal aspects are murky - I'd expect id has a strong case if it's true, but the developer's in Russia, so likely only the American distributer has liability. But I think you're trivializing a theft here from a company that has set a much higher example then many in sharing their intellectual property. For some reason, I think they just deserve better.
Edited - fixed spelling of "id"This comment was edited on Apr 7, 02:18.