I haven't commented on the animations, though I find them decent enough.. I had been suggesting better animations on the feedback page but the new devs didn't work on it or any other combat related issues, sadly.
What I was mainly referring to was the one mouse button option. If you think about real life sword combat it's silly to think that there would be one stance for attacking and one for blocking. You would be in one stance hoping to block and attack well from that position.
Blocking on RMB makes sense for shields, however. Okam had a second option to block with them, too, although I always thought they did a poor job with it. Blocking with the shield should be your first option. That's what you got it for. Yet, in Okam it was so unreliable that you couldn't actually use it in Melee combat at all, so your best chance was to utilize the LMB weapon block function and only rely on your shield for passive protection.
That's one thing where I thought Warband's force field shields were the better mechanic.