My train of thought is that the scape should always benefit the fish first and foremost. The scape materials must be usable by the fish.
A carefully scaped tank with a false slope (like a lot of those "forest" shaped tanks or such that create an illusion of depth by using a slope and such) does not benefit fish that would use a wider bottom, so usually only a school of upper level fish are there to enjoy that type of scape. It would not benefit bottom dwellers one bit.
A community setup is near impossible for this. A small shoal of upper level fish is really all that can use that space.
Opposite end of the spectrum are iwagumi setups. They're often open with just carpet plants and a couple rocks. They do not offer enough shelter for many fish and a lot of the fish choices the "scapers" use are often poor options who won't enjoy living in an open space like that. So that's also something to keep in mind with scaping. It's plausible to be too empty as well!
Lots of rocks can provide shelter and many fish enjoy utilizing rocks. Gobies, hillstream loaches, plecos, etc. But piling them too high in the tank takes up swim space for upper levels, so again, you'd not really want to put these.
Any time we scape our tanks, our focus should always be "how would my fish use this setup". If the hardscape takes up a lot of space, then yes, it is going to affect your stocking choices and limits.
It takes a lot of thought and practice to balance it out and learn it.