The idea itself is perfectly fine, it comes down to details of execution, freedom of choice how to play the game is surely a good move, nothing beats ability wheels, from campfire in the forest to castle-city with enemies heads on the spikes on the walls, you can add some special resources onto tiles so they can be upgraded with some special type of a building after the game progresses and enable some middle to late game upgrades
Im a big fan of city building paradigm. I assume you aim at linear left-right open map? Are you considering for example as a one of game modes the arena that is open only to the right side? That would be the most simplistic and compact take with enemy kingdom on its right end.
Some battles of armies where they crash into each other like waves of water (Asterix vibes), general goofines of how stuff happpens. Without seeing full gdd its kind of hard for me to discuss or come up with anything other than loosely tied ideas. Are you considering mobiles as a target platform? Because that also changes a lot of how stuff has to be aproached both in engineering and design.
Generally, everything is connected to everything else—it's just a matter of the level and the way it happens. Also you can add some small elements of simulation, like women, kids, families, people having and expressing emotions. It doesnt have to be strictly whack-a-mole type of game :P but thats just random ideations