I thought of something similar after finishing the game, but instead of playing as Zelda, doing it with Link as side missions requested by certain characters. You know; peace has come (except for some new evil growing in the shadows, maybe the Yiga Clan getting stronger and trying to bring back Ganon like in Zelda II), so Hylians have come back to their previous, raveged settelements (as you said, the ones found scatered through the map, plus Hyrule Castle Town) and now the need to rebuild them. So you will help them do it by completing all kind of side missions; getting wood and rocks for new buildings, protecting waggons which carry materials from bandits assaults, cleaning certain area rich in resources which is plagued by monsters, defending a small town from an attack by the Yiga Clan, carrying certain materials from an area to a village in a limited time without letting it damage, opening and/or securing new routes for transport and commerce...
I can think of hundreds of posibilities for the DLC (and yet I feel that, if the strictly stick to what they have announced, it is going to be really dissapointing).







