I see waterlogged trapdoors already as a quality of life change from Mojang because you no longer need to waste so many bows for crafting dispensers, instead, you have trapdoors that are even cheaper to get. Of course, it requires a lever instead of a button now.
But with a warp totem, you can create your own mall or a shop in the size of the mall with more features than a mall allows.
Your solution would make warp totems become obsolete and too expensive to place.
Would only make sense, when the mall-warps lead to another dimension where all shops are inside a cuboid of bedrock with each shop being 16 chunks away from each other.