Well, most people possess MORE dexterity than I have to be honest, and I find it very easy to do.

Unless you have physical limitations I can't fathom how holding the right mouse button and pressing space is hard. Why? Because it's not. It's only two keys and the right mouse button if you want to dodge in a specific direction. If you're in a fight you're already moving anyway, or should be, so all you have to do is block and hit space. It's no harder to dodge than to do anything else in a fight. If you can't hit the space bar while holding WASD and using your OTHER hand to hold the right mouse button... well... I don't know what to tell you. Practice for a few minutes, maybe?