Anyone got any ideas which games you believe GOG will never be able to bring back?

My money is on:
No One Lives Forever, Simpsons Hit and Run, Mafia 2, Escape from Monkey Island

Games with 3rd party licenses that will not sell that well. Which unfortunately means most racing and sports games that uses real life teams and brands.

NOLF and Mafia 2 are still possible, even if unlikely.

Myth
Old Mechwarrior/Battletech Games
Warcraft/Starcraft/Diablo
Half-Life/ other Valve titles
Cryostasis
XIII
Lord of The Rings: Battle for the Middle Earth series

I wouldn't bet on Escape from Monkey Island. It wasn't a bad game. It was 3D with awkward controls, but it was a pretty good game.

I LOVED Escape from Monkey Island. Despite the move to 3D, the game didn't become a bland exercise in block pushing and platforming (Broken Sword 3!) and retained it's outstanding humour and ridiculously abstract puzzles.

I'd love it to come back through GoG, but can't really see it happening.

Still, the shit they went through to bring back the Gold Box AD&D games... Never say never!

What's the issue with Escape and Curse? I mean we have Grim Fandango, Monkey 1 and 2 and DOTT. They seem like obvious candidates to sell well.

System Shock 2

Interplay's release of Fallout series.

The only golf game with Dinosaurs in it World Tour Golf
The easiest cricket game: Cricket 96 (where scoring a 1000 runs in an innings is possible)
Lemmings :P
Arkanoid series

Toca Race Driver 3
Colin McRae Rally 2005
Race Driver: GRID

Ok, I don't understand what the OP means.

If it means to bring back from the dead, then some of the games posted (blizzard, for examples) are already working and can be bought, just not on GOG.

If it means games that GOG won't sell here, well, they reject a lot of games, including old ones. Basically, most old games that they don't think will sell enough are not here. I have my own list of old adventure games missing from GOG and it's huge.

Buck Rogers: should be public domain but the dille estate sues the crap out of anyone that tries. anyone who tries to work out a deal with them can be expected to get the crap sued out of them by warner bros/sony because they believe it should be public domain - it's a no win situation. Both sides are waiting for someone to make the first move so precedence can be set. GoG doesn't want to step into that minefield.

Dune: the Herbert estate just refuses to let anyone do anything with the property period.

I'd like to see your list and is there anywhere else these games can be found?

Chex Quest
Psygnosis titles
Flashback?
Blade Runner maybe
The Thing (although they have AvP here, i think publisher was the same)
Don't know status of Blade of Darkness, hope it returns
The Neverhood
Old Prince of Persia games

Dark Sun Online: Crimson Sands (ancient MMORPG that no longer exists)
Darkspore (has always-online DRM, and the server has been shut down forever)
pedit5 (probably the oldest known computer RPG; apparently this game has been preserved, but I am not aware of a version for modern computers) and possibly other games of that vintage, some of which we may never know about