After playing for a few hours I have to agree. My mouse hand got tired and I found myself wishing I could swap to keyboard movement for a while. I play FPS games with an old school setup of the Right Mouse Button as move forward, so I'm used to holding down RMB and moving for extended periods. I guess my index finger isn't used to being the one to constantly hold down the button, and after a couple of hours straight my hand was hurting.
