So I just thought it would be cool if there were adventures that gave friaries or silos or watermills or village schools or even endless copper mines (yea, I know, dream on) in the reward, like they sometimes give castles and witch towers and stuff. Perhaps only adventures which are sold for gems (but could still be got from adventure search).
Just a suggestion but I think these new joint adventures weren't very popular when the idea was introduced, so getting a non-deco building in the reward could perhaps sweeten the deal?