It would be cool if there was a place wher you could trade you buddy dolls to complete your collection. It could be an unlockable place, if you find x amount of buddy dolls then you can start trading doll for doll. You could only trade them at the center though. If you try to trade them outside of that you can't besides the generic buddy doll.
This could also be extended to if other townsfolk become dolls in the future. Adding a little trading card game (for lack of a better term) would be a fun add to the game and build mroe community and encourage player interactions. Of course trading would not be manditory. You can still trade with buddy and hope to get the doll you want. This trading center would benifit the players that have been building their collection for a while and have a lot of duplicates.
Another thing that could happen besides a player trading center could be if you have x amount of the same type of doll you can turn them in and choose which doll you want or have a player turn them in and get another chance of getting a random doll.
I have only recently relized you can trade the dolls with buddy for more dolls and I would really like to see more like this in the future