You are just seeing the obvious part of that design.
The problem with it is that the protocol between the pool and the harvester and eventual harvester plug-in is not there to support additional harvesting modulles. This is where Chia screwed up, and as such third-party developers need to go ass backward to get things done (e.g…, NoSSD).
You could imagine that the harvester is able to work with plug-ins, and that there is a protocol that would enable pool to exchange data with such harvester plug-in. This way, the pool would be able to enable such plug-ins to work just with that pool. All the rest would work as it is today, thus nothing would be violated.
Of course, this is only with respect to NFT plots. The ability to create OG plots should be buried behind 10 clicks the day they released NFT plots, yet for whatever retarded reason those plots are still default ones making pools like HPool / Foxypool, etc. harder to kill.