One of the elements that was prevalent in older tabletop games was a concept of leaders directly.. well.. leading their units. The main title I keep thinking back to is Napoleons Battles. In that, a unit can only be ordered if a leader model was within range, else they'd either hold or at best, return fire. I'd played many games with this mechanic and always thought it gave a sense of value to the leader units beyond their direct combat utility.
Modern titles reduce heroes and leaders down to a morale bonus at best and at worst, mostly redundant. To me this feels like a shame and a missed opportunity. The leader, as part of the hobby is going to be a centrepiece to the army, and as part of the gameplay should feel like the core gear that an army turns on.
In Charge then, my initial approach is to make them both a powerful unit and a centrepiece of an army. Leaders begin each turn with an order pool. They may issue any order to a unit within their radius, including themselves and other leaders. They also may function as a bonus to morale checks (depending on the army list) and / or also function as a powerful hero unit. In this sense I feel like they'll act as directorial units. A powerful melee hero leader with a small pool of orders and limited range will naturally pair well with cavalry or shock troops, where a more strategic leader will offer options to a wider set of units..
This also creates opportunities for vulnerability within an army, as a unit without orders cannot do much. That aforementioned hero unit might be killed early in the match, opening up opportunities for a counterattack.
There's a ton of edge cases this opens up, like losing all leaders early on, or not having enough orders to cover the army, but I think that the overall opportunities for interesting tabletop storytelling outweighs the potential issues. I also feel like modern techniques for handling individuals lend themselves nicely to keeping them alive long enough to be effective.
All this is to say I'm still exploring the subject within the game, but I do feel that it'll feature heavily.