will gog put mods as special features for certain games?

there typically is a mod thread in every game forum, I don't think they'll ever host the content locally.

To further Weclock's statement, the GOG team is usually the one to make the thread in the first place along with all the links to the most popular mods for a particular game.

i just thought it would make sense to put the better mods that were created for some games in as special features

... So GoG pretty much takes responsibility for them? Nah, it's best the way it is - seriously, not like it was so hard to click a few times

It doesn't make sense for GOG.com to host free content like that. In the case of Lure of The Temptress and Beneath a Steel Sky, the reason they're hosting them for free is that it allows for the possibility of other games from their developers back catalogue.
Maybe, severely maybe they'd host mod content if it was directly related to GOG.com and very high quality.
In the case of UTGOTY, they won't even host the hi-res textures which came with the original retail disk.

It might also be a liability issue for them to host the mods. Plus, would you want people emailing you for support for a mod that causes issues with your game even though you had nothing to do with mod itself?