I agree the vegetation is fine I find it adds to the challenge if people want less they can use mods like Regrowth.The only suggestion I have is that you find the reason for the invisible buildings fix it then work on adding more even though as it stands I personally dont think it needs more.
Love the mod but you really need to do something about the invisible buildings and the missing floors walls and ceilings I see inside some structures.Im running two 1080s so Im not having a real issue with fps but there are still some bad areas.