Good list aside from the awful Little Big Adventure and 1-2 others.
Even so, I don't think anyone can say that GOG user reviews aren't massively inflated. And I say that as someone who loves the site and owns far too many GOG games.
lba now it's dated but back them was awasome. The thing is the most problematic thing about old games are that they are somewhat clunky and most of the time offer bad graphic. But it's clunkines is something you can learn and sometimes is created that way because of reason. In Gothic 1 there is some most clunky system for fighting for new people, but it was created to fight in this game with tactic. If you learned new move you actually had to do this move no press a for awasome.
But above is only true for two first hours. If anyone can menage to play it for 2-3 hours you will find magic.
Thief looks bad now but it's gameplay is stellar and looking at AI of opponents in that game opponents in new games have braindamage.