What if more civs could make a unique building like the Portuguese or Malay?

The Feitoria has already been an ongoing subject of controversy for largely balance related reasons, but I have also always found it interesting that a civ with two unique units also has access to a unique building. This gives the Portuguese a lot more flavor to them than they would otherwise have.The Malay are similar but the Harbor is more of a modified dock although it can also function as a sort of stone-less guard tower in certain situations. The idea of having a unique civ building seems like more of a recent idea from the devs to set apart and bring fresh identities to new civs where maybe some civ bonuses would prove insufficient. Are there any existing or future civs that you think could use a unique building either for design or historically justified reasons? Some civs with only one unique unit and weak or situational unique techs come to mind such as Persians, Teutons, Saracens, and Vietnamese. Other civs by virtue of their long and compelling history also make good candidates such as the Chinese or Byzantines. Any architectural historians out there with any ideas?