My old card was gt440 and it ran Wasteland 2 beta pretty well, especially after the last update,l on full HD and only AA turned off. There was some lag on the frame rate on particle heavy maps, but overall the game was very playable.
They've been optimizing it all the time and improved performance quite a bit during the process. I'd guess they'll continue doing that till the official release.
And the game is, indeed, pretty huge. The beta area alone is the size of what most games would call a whole game. There's some voice overs, but only on important characters and no pre-rendered cutscenes. Only thing of that nature is the opening cinematic, at least for the time being.