I'm just going to say that there's a decent chance that Samurai won't be using a Dai-Katana due to it being a weapon type of DRK. However, the use of a regular sized katana, or even the Katana/wakazashi combo would seem more likely.

I'm also more in favor of them being more proc based than rotation. I'm also really hoping they include Kiai's, either as a self or party buff, or just an awesome attack a la Fus Roh Dah.