Setting up shops inside your house would definitely be a bonus. I miss the bazaar system from FFXI. Only having the market place for selling makes it a pain to sell items at times. With the "market place only" system you are always in direct competition with every seller. This may be good for buyers, but not so much for sellers. It also eliminates the ability to capitalize on convenience and impulse buys. There is something to be said about being able to make a fair profit off of people's laziness (convenience costs). I don't consider that gouging, so much as providing a service to those who don't wish to spend the time to go elsewhere and get it cheaper. They could still go find it cheaper elsewhere, but they chose to purchase the slightly higher cost one because of the convenience of it.
That reminds me a lot of PSU's system, whereby everyone got their own room, and you could buy an "upgrade" to include a shop in it (with a coded lock, in case you didn't want anyone to access it). In theory, it's fun, but in practicality, the Market Boards in this game make shops in your house pretty much useless. Though, as you said, FFXI had both, so this could as well, but that would require a whole new dynamic for the retainers (one for Market, one for Bazaar?), and is probably not high on their list of priorities.
Not to mention, much like the previously mentioned FFXI and PSU, a lot of people will just put up hempen underwear for 999,999,999gil, and waste your time looking at their "wares" (or, would that be "wears" in this case).
In any event, I'm just happy for more content that everyone can take part in and utilize...even if they don't need/want to...