In January 2018, there is no support. You can not wait for the support of achievements, they just scored on it. could at least promise to present it for the franchise's birthday or honestly admit to the fans that there will never be support, so that people will not wait.
Yeah, I don't particularly care about achievements (unless they're in-game stuff) but I've got at least one friend that has played TW2 on Steam because of the lack of cheevos in the GOG version. They should be clear about when (and if) achievements will come to GOG games (it's not just a TW2 issue), because maybe they don't know it, but they're losing sales and users because of that stupid little thing...
in the Steam version of the game, in addition to achievements, there is also a leaderboard with the results in the arena. I can understand that the game is old, and developers do not use the introduction, but this is their store and their game. I returned the money and bought it on Steam.