Love seeing your though process on this, I have been thinking about this subject on and off for years. The best thing I can come up with is delayed swaps like Hive-HBD so the algorithms that govern the bots can average the swap price with others that want the opposite swap. Unfortunately this is the opposite of why people pick lp swaps on the 3 second block time for almost instant settlement or rejection of their offer. The other option is a forum where people can request swaps and others can just accept the offer, but again this is a slow process and can be exploited. Maybe my ramblings will give you some other inspiration to come up with a solution I have yet to see.
I have only seen one person try the non pool swap on Tribal Dex and he was not happy about the 2 day wait for the swap to process.
Edit: The biggest hurdle to overcome on this is a basic computer science problem of with working with n log n calculations.
RE: Impermanent Gains Part 2: What is a "cross-swap"?