It's called "Art Direction" for a reason.
Love it, hate it, or leave it - it's a fictional world, with fictional rules, and (gasp) fictional weapons. BW's artists have rendered that world, the execution of those rules, and the models for those weapons in ways they believe will enhance the story, attract a variety of diffferent players, and - hopefullly - support strong product sales.
This reminds me of the endless debates on the ME2 forums about why the majority of the NPCs wore simple rebreathers, rather than full helmets, when wandering around hostile environs. What I found most interesting was the amount of angst - and I mean real anger, supported by real (and sometimes quite marvelous) science that presented a strong argument (though why one was needed was beyond me) for why these characters needed helmets, else "immersion" (whatever that might means) would be "broken". The case for more realistic physics / helmets and what-not continued long after the game was released, and long after 99% of the fans played through the game and either a) didn't give a **** in the first place, or

shrugged and said, "it's a game, so who cares".
Moral of the story: I hope you (and here I'm addressing the vocal minority of fans who have seen snippets of the game and have decided that 2-handed weapons are too large) aren't holding out too much hope about getting the size of said weapons reduced any time in the future, because it's not going to happen.
And by the way - I'm pretty sure BW slowed down 2-handed weapon animation, not because a number of realists believed (and - I'm sure - quite rightly believed) that they were unrealistically fast. Rather, it was a game balancing issue that was easily addressed by reducing the warrior's standard AOE DPS by slowing down the animation. Added benefit: more "realistic" weapon speed, whatever that means.