How to improve the look of character walk cycles?

I would like to improve the look of my character’s movement. Currently, I do a MoveTo on the character and he moves smoothly towards his target playing his looping walk cycle from his blend space. This looks at a minimum stiff for humans, but really really bland for any creature characters. For instance, a shambling zombie should not move smoothly. Another example is a T-Rex should show big changes in speed as it moves.

I was thinking RootMotion would be the answer to this, but it looks like this is limited to canned animations, not walk cycles. Root motion turns off rotation controls and path following.

What is the suggested way of controlling the movement of characters in this way if Root Motion is not the answer?