this game have people playing online? or is it dead?

I'd say it's mostly moved to Steam. The latest patch isn't available for GOG users and supposedly uses Steamworks for multiplayer. Of course, that's a guess. I've only played RotT in single player.

The community on Steam gathers pretty much every saturday night for some matches so while a small group they seem dedicated. The thing is since the Steam version got the 1.5 and GoG didn't that instantly segregated the playerbase so we can only hope to have 1.5 here as soon as possible.

It is a Steam game now. I bought with spare trading cards credit on steam, but you might ask Interceptor for a steam key with GOG's proof of purchase (I think I read something about that somewhere). The version on steam is DRM-Free too, you can launch it withouth steam (once installed, obviously). The last patch is steamworks, so don't expect it to be released here. There are not a lot of servers, but with steam's game I can play online sometimes (I don't try to play it very often though) and (almost) every Saturday, there are games.