Pond Boss Forums POND CONSTRUCTION Creating habitat Is too Much Habitat Possible?

I've read that, the 20% advice, but what about 20% makes it ideal and why would it not be good to cover your entire pond with structure? I understand different fish require different habitats but it seems all fish would benefit from cover on the entire pond. Peepaw, I've added a lot of brush piles already and cinder block hotels, but I'm likely going to build some 6-7 foot tall PVC porcupine-like trees among other artificial fish habitat.