Thematic settlements that mattered to the game rather than just being "fluff" would be a nice spin. I have not "played" Descent or "Roads to Legend," but I have read up on it a little. The differences (minor / mechanical) as they are did seem appealing.
A variant would not be too hard to implement for this.
Last session we played with Frozen Wastes and I thought about something for the base game:
- Only keep Challenges in the Adventure Decks
- Shuffle all the Encounters and Events cards to create a "Settlement Deck"
- Everytime you end your movement in a city you draw a card from the Settlement Deck
That way, I think, it would speed up the game a bit (adventure counters providing only Challenges) and would force you, at one point, to get into cities to replenish adventure counters and create events. Sure it'd be better if you have some Challenges deck expansions to add more cards in the decks…
Sure it's just a draft and a wild idea and there's some work to do to implemtn it in a game but maube i'll give it a try and see how it feels!