One suggestion for categories:
Site Design (or simply design in general). Each of the pep "areas" are great in and amongst themselves, but only solid thoughtful design can bring about synergistic interactions among all of them. Perhaps, this is a category that would be unlocked only after having completed a set number of other badges. Bits could be measuring/surveying (ie, measuring the space to be designed, and then laying out features of the design), energy flow diagrams, interaction paths, nutrient capture and paths, water capture plans, zone layout, etc.)
I understand design is an integral part of everything that is already mentioned even down to the club mallet, but I think that it is of great importance to emphasize the purposeful alignment of all the elements for their maximum potential with the fewest input.
Perhaps also part of the same category or an entirely different category would be Water. Water Capture, Acuaculture, Acuaponics . . . maybe, pond building, dam building, swale construction, etc.
Just a few ideas.