I have mixed feelings on this. Admittedly it looks gorgeous, and it'd be neat to play for a few hours. But something tells me it would get boring pretty quickly. I've always had that romantic view of the medieval period of hist'ry, with shiny armor and hot princesses, etc. But this game looks to be more about riding horses, slogging it out in alleys with drunk idiots, and being a low-level pawn who can't afford nice armor.
It's real, yes. But the real medieval period was tough, violent in a not-fun way, dirty, depressing, everyone had bad teeth and smelled, and a good percentage of the folks you knew died young for one reason or another. I just don't see the appeal in living in that world very long, other than for morbid curiosity.
That said, it brings up an interesting concept in gaming: historical super-reality (or perhaps someone can come up with a better term). Perhaps someone will make a realistic piracy game, where you really have to wipe your butt with chorded rope and puke over spoiled rum whilst lost at sea for 3 months of real-time game days seeing nothing but the open blue and the toothless psychopaths in your crew. Or play as an FBI agent in the Prohibition period of American history, where 90% your real game time is spent doing paperwork at a desk and only rarely do you put axes to barrels.
Some people would probably really enjoy all that.