I've always wished they had taken a different approach to DLC and offered up smaller animal-only (1-4 habitat species) and scenery-only (50-100 pieces) packs between the larger ones. Or had sometimes released an animal-only pack plus a scenery-only pack so the two didn't have to be connected.
It would open up so many more options as far as scenery goes! Imagine the possibilities... An "education" pack that would include museum elements, additional guest facilities, new signs, etc. A "parks and gardens" pack with flowers, slate pathing, more fountains, various decor, etc. "City streets" with a new sidewalk path, power lines, parking spaces, cars, building facades, and various clutter.
Frontier has found creative ways to implement "generic" things with packs (or just straight-up add them in free updates which is always appreciated) but I've always felt like the pack structures and themes were pretty limiting in a lot of ways. One of the reasons why I'm really hoping a final pack has a hyper-generic theme and includes scenery as well as at least 8 habitat species TBH.