First and foremost they provide separate biomes for more species to occupy niches, beyond that they have little distinction at the moment
The mesopelagic is actually a haven for scavengers right now, with the highest rate of occurrence of marine snow, with the bathypelagic receiving some to a lesser extent.
The sea floor however is merely a barren place with nothing notable at all, but that in itself might distinguish it from the others.
Indeed, if there were less patches to navigate through, there would also be less patches for the AI as well.
I think adding a new path from the vents to the bathypelagic might help a bit in that regard, and potentially to the caves as well to make travel to the mesopelagic less linear.
I would also connect the estuary to the epipelagic, or atleast swap it’s place with the tidepool as it makes more sense for tidepools to be isolated.
Finally, I would connect the ice shelf to the mesopelagic in addition to the epipelagic.
(Quick presentation)
Personally I’m rather hesitant to just drop the patches, and would rather put some effort into differentiating them instead. We’ve discussed terrain generation in the past as a potential solution, but I would also like to see unique environmental hazards similar to the ice shards in the shelfs as well.