I'll be honest, something like split lot types is a system I have wanted before lot traits were even a thing. Anything + residential. Bakery retail + restaurant (really anything + restaurant). I'd also like spectors for community lots. I know you can make everything "haunted" technically, but spectors are begging to be in some sort of makeshift graveyard or creepy library. Also, rentals drive me crazy with this in particular since they are so close to normal residential. Why can't there be a spector haunted rental?!
So I am all on board for lot hybridization and maybe some lot trait/challenge versions of lot functions. I understand that this may well be a tall order and that why some things may just have to have a watered down variant as a trait or challenge, but it would really open up what we can do with our existing lot systems.