I'd like to see GOG Galaxy support virtual LAN over the internet, similar to Hamachi, Evolve (not the game), etc. This would allow multiplayer on older games which supported LAN play.

I liked Evolve's approach where you could start a "Party" (group chat) with people in your friend list. Anyone in the group chat would be part of a virtual private LAN, as if their computers were connected locally, but runs over the internet. You can then use the virtual LAN IPs to play LAN supported games.