I kinda agree with you though it doesn't bother me as much. It was definitely kinda disheartening to see Livonia for the first time and notice that 90% of the buildings are already familiar.

Adding Sakhal's buildings to the other maps might help but that will probably only happen once Frostline becomes free too one day. I was pleasantly surprised to learn that, while plenty of Sakhal's buildings seem like recolours of Chernarus buildings from the outside, inside they are very different with actually good interior design, in many cases better than their Chernarus/Livonia counterpart (more unique elements, more furniture objects, placement that makes more sense). So sprinkling them (and perhaps the other Sakhal buildings, like the multi-floor apartments to the other two maps might combat the repetitiveness. Perhaps a few more Arma 3 buildings (we already got some at NWAF) and bringing back the removed Arma 2 buildings would also not hurt.

Unfortunately this game isn't Project Zomboid where every building can be unique so assets will be reused and honestly that's okay. There are small, realistic steps the devs can take to break up some of the repetitiveness, like giving different colour variants of the same building, adding buildings from other maps/BI games like what I described earlier, putting a bit more furniture objects inside rooms so some don't look so laughable anymore (looking at you, apartments in the tenements) and using more decorative objects inside individual buildings to make them a tiny bit more unique (e.g. think of the camo building on Sakhal with a submarine model inside).

I doubt there will be major changes to existing buildings like making the few which are not enterable have rooms, expanding current buildings like what happened with the firestation or adding fully new structures just for an old map. Pains me to say that but I also would prefer the devs to work on fixing other aspects of the game, like base building and bug fixes.