Thanks for the info! For more reference on the foot design you used, try checking out some of the animal reference photos available here at dA. I believe that what others are trying to say with "too much reverse foot" is you may want to try raising the angle of the middle portion of the mech's foot.
In animals, there's a tension created by muscles that keeps the central lever portion of the leg from dipping down that far in the front. Try looking at cat, dog and horse legs for reference.
You've got the seed of a really good-looking design here. Keep it up!