Finished it, the sacrifice thing was a bug that was fixed by saving and reloading. All in all, I kinda liked it, especially when the AI sent wave after wave of soldiers when I attacked one of its main bases, I hope it's always this aggressive. I sucked at controlling heroes properly, mainly using the spellcasters, but I also didn't try to find out how to change active abilities (if you can change them in combat at all). I see the RTS part devolving into death-ball tactics, however, the basic soldiers are all samey and incentivizes massing them. The game says there's some rock-paper-scissors thing going on, but I didn't notice anything like that as my death-ball was ravaging the whole map regardless of anything. I'm going to pirate it when it comes out to see if they are going to build up on the things shown on this map or if they chose this one because it's the best of the lot.
You are very on-rails with the story, though, I tried both not sacrificing my soldiers and doing it and it all led to them being sacrificed, I also didn't want to give the artifact to the very obvious traitor (it's obvious the moment you meet him), but the game forced it anyway. Kind of left a bad taste in my mouth, but I know I can't expect anything more, even though there's an RPG part to this RPG/RTS hybrid.