GOG servers are absolutely empty. So for the same price here u can buy a dead game, compared to Steam. Very dissapointed. If this will happen in DL2 - Ill just skip it

For the simple reason that the steam version uses the steam network, which GOG has no access to.

The publisher would have to offer it's own servers without using any of the two platforms to allow crossplay and my best guess is that they don't want to invest as much.


I don't play MP anymore, bought the game for single player only.

I really wish they would, we would get all the cool missing DLC content, I have both version installed I notice a tad more people on the Steam version lately but it cut down since 2015

Im afraid the DLCs have nothing to do with multiplayer networks.
No, we could not get additional DLCs if crossplay was available.

Under no circumstances it will ever work that you buy a game for one platform and a DLC for another.
These are entirely separated licences. Once the publisher releases DLCs here, they will be available, not before.