I think it would be awesome to have a secondary house. We don't have enough space in our notable homes to do as much as I'd like to (furnish and build a Library). I have several homes but people can only visit my main house. I want to create a Lore Library with tons of cool stuff from my adventure, but my main house isn't capable of being both my house and that at the same time without being supremely empty. Therefore, I think at minimum, we should allow people to visit secondary houses as well, though the best thing would be a drop down list so you can visit all of the houses someone owns.
This also happens to be the reason I haven't bought anymore homes because what is the point if I can't show people, or have to keep swapping primary residence?
Yes, I do heartily repent. I repent I had not done more mischief; and that we did not cut the throats of them that took us, and I am extremely sorry that you aren't hanged as well as we.
— Anonymous pirate, asked on the gallows if he repented.