What would you add to Heroes? (creative ideas only!)

I don't even know how to implement a mission selection system in the fifth game. At least in the third game, there was a general map, but in Heroes 5, you can't even choose campaigns; they all have to be played in a strict sequence. Although, this isn't necessarily a bad thing; it's just that I would like some variety and a departure from the meticulous sequence. Let me explain: in the third game, for example, you are given a certain number of campaigns to choose from, and after completing them, others are unlocked, but once you start a campaign, you play it to the end and cannot jump to try another. In Whirlwinds, it's a similar story, but you can play several campaigns and "jump" back and forth between them, and when you complete one, it is immediately marked with a checkmark that doesn't disappear later (whereas in the fourth game, you have to load from a save). I would like to see something similar in the fifth game, so that at least a small degree of freedom of action is provided.