I think that having a cast bar on samurai skills would actually be cool. Not on every skill of course (and I think the trailer backs that up), but maybe on their combo finisher. Like, "slap, slap, charge-up slap".

Now, why not allow the samurai to charge up a skill... and move while charging it? It looks like he sheaths his sword, and then takes it out for his powerful attack. He could keep it sheathed while he moves, and when he comes back to the enemy, he unleashes it.

If the skill made us hold the hotkey to charge the skill, I can see this being a real possibility. It would also make it so the samurai isn't animation locked, and it would keep the flow of combat going even while dodging aoes.

(Purely speculating here, but it's interesting to think about!)