Strategic game mode

As I've explained elsewhere, the vision for the game includes some elements of strategy and conquest to go along with fighting armies and burning castles. I've previously said that the closest similar game that comes to mind is Mount & Blade, but what exactly does that entail? When I say it's inspired by M&B, I mean in the general sense that it's an action RPG/strategy rags-to-riches sandbox type of experience. But it will be quite different in terms of mechanics, especially since I want everything to happen in the same open world in Dragontwin, instead of splitting the world into an "overworld" map and multiple smaller maps that you load into like in M&B. I don't think there has ever been a game where you play as a character in an open world while simultaneously being able to have huge, Total War scale battles in that same world without loading into a separate map. Remember in Skyrim where they hyped up this epic battle of Whiterun and then there's like 15 guys who show up because their engine couldn't handle any more soldiers? I don't want that, so I've been thinking a lot about how to do this.

 An idea I've had for the strategic aspects of the game (like army movements, income from settlements, etc) is that it all progresses in a turn based fashion where the player can move pieces around on a kind of war table / map of the world (similar to for example the table in Dragonstone in GoT/HOTD). So if you want to move an army, you move its piece to a valid location and end your turn, and then the AI factions play their turns until it's back to you again. This is then reflected in the open world, with the army now being encamped in the location you moved it to, or preparing for battle if you attacked another army, or besieging a settlement if you did that. If you chose to engage a hostile army, the armies stand prepared in that location in the world and the player can fly there to start the battle (maybe swooping in from the skies and sounding the dragon horn like in one of the sneak peeks). As long as you don't end your turn, the strategic landscape doesn't change and you can close the strategic map and just fly around in the world as you wish without worrying about being invaded. However, you also can't expand your own kingdom, recruit units, etc, if you don't end your turn so it goes both ways. The goal is for the strategic aspect of the game to be pretty simple but fun, both because of the varied player base (many casual players) and it needs to work on consoles.

I might make a small, primarily visual prototype for this at some point to see if it makes any sense, so don't worry if this explanation was confusing as it is much easier to understand with visuals.