great looking T-Rex, here go my comments.

1. Step - Stop - Step, seems to robotic. Have it more fluid, less of a pause between first step and second.

2. Have the head start to rotate with the first step.

3. The leg goes into the body, you might have to solve that by some weight adjustments or maybe by deformer.

4. Have the tail swing out more. I love how it starts to swing out but then I feel like "Man why didn't it keep on going."

5. Have it go a little faster and add an extra step.

6. Where is focal point for the dinasour? Where is its prey? Make sure to have that in mind when animating the head.

I hope this helps