There's no reason an improved instanced system couldn't exist side by side with wards.
The improved instanced system could even be accessed through the wards just as apartments already are. I think all the housing districts have areas that are unused dead ends. Turn the dead ends into the entrance for "private estates" (would need a better name), which would be the new instanced system. It would give the added benefit of more traffic in the wards as those owning the instanced housing would want to go back into the ward to access marketboards or vendors or the "recreation areas" (like the Brimming Heart or the Shirogane hot springs) on occasion. It would give everyone a house at the same time it improves the "neighborhood" feeling that the wards are supposed to provide but don't.
Most of that makes no sense when all housing interiors, whether house, FC private chamber or apartment, are instanced.
They already co-exist.
The only reason I've personally heard him give is that they like the social aspect of wards and yet they fail in that regard for the majority of house owners.
- There's a limited number of owners in each ward/subdivision, usually with different schedules on when they can play the game.
- If they are playing the game, most of the time they're going to be doing other things instead of standing outside their house in the ward where other players can see them (like playing around inside of their house where they can't be seen).
- Lack of reasons to travel within the ward not to mention the aethernet shards that can take players directly to their destination those rare occasions they do need to means greatly reduced chances of random encounters that lead to socialization.
- If socializing is intended to mean hanging out at the FC house with your FC members and their invited guests, or going to a RP venue, that can be accomplished through instanced housing as easily as a ward. RIFT has a great system for helping players find and travel to other players' housing, not to mention the whitelist and blacklist features that frequently get requested for housing here.
SE need to stop believing they can train the player base to use housing the way YoshiP wants it to be used and start looking at the actual experience house owners are getting on a daily basis. I love my house, I will visit it a few times each play session but I'm still spending 90% of the time I'm logged in doing other content, 9% inside of my house and only 1% standing outside of it. Even last expansion when I spent about 300 hours sitting in my yard grinding out my Expert crafting achievements, I only saw 3 players randomly pass by my house.
If a player is after an actual social experience, they're much better off hanging out at the Limsa, Ul'dah or Gridania aetherytes where players actually gather to socialize and other players are constantly passing through.