I don't think we'll gonna see Forgotten Sands on GOG anytime soon.
Ubisoft is a drm b1tch and they won't give up the DRM of this game just to release it here, since it is already on Steam and UPlay (both with DRM).
Judging by history of official releases of Ubisoft games with scene cracks (because lame ubi does not keep unprotected exes and cant even recompile exe from sources) - they cant easily release Forgotten sands on GOG with yet another scene crack that removes ties of Uplay.
But if you did not pay attention to series of Ubisoft decisions in last 10-15 years - this company is controlled by totaly idiotic managers who cant come up with any wise decision.
I used to love Ubi up until Assassin Creed 1 \ Far Cry 2 \ R6 Vegas \ SC conviction era that ruined whole Ubisoft since every game since then start to be build like LEGO from assets, code base and design documents of named games, so every Ubi game (with some minor exceptions like Rayman Origin and Grow Up, which are more like indie games made at spare time by Ubi employees during work on bigger games) nowadays is Assassin Cry Vegas Conviction and anything that does not fall into that cathegory is considered non profitable by Ubi and they barey care about it, and this also includes their legacy games that made them what they are now.
They are so careless about their legacy, that even some HD remasters which they almost never release on PC, got outsources to some cheap and low quality Inidian studios that screws everythig up and give no fracsk about things like broken lighting and post effects, poorly done unmatching HD texture and ugly looking new UI and tons of new bugs....
Ubisoft needs to fire every current manager and hire someone with brains and care for Ubi legacy and creativity that this company used to have prior 2007-2010 era, only then we can hope for something good from them.