A couple of things to tryout or consider if you haven't already. First, use a prop saver and not a collet mount for your prop. Second, find out how to program your esc to have a "soft brake" or "free wheel" on your motor, once your have this working the motor and prop will usually be much more forgiving on impact with the ground. Third, (this will increase weight unfortunately) find a way to beef up the landing gear to somewhat reduce the flex or spring within the gear legs.
I second what "ahicks" suggested.