IC: A new kind of strategy game
That might be a bit too simple. I want there to be depth of strategy in both the command of party members but also in equipment choice, use of environment, and attack style choice.
I'm thinking more strategy game with a few rpg elements, where your available people are your greatest resource.
The strategy I'm thinking of as being similar to Starcraft and Fallout Shelter mixed together. You might assign folks to collecting loot, crafting items, growing mushrooms for food, protecting a fountain of water, raiding the next dungeon, etc.
Of course, those things need to matter or they'll be pointless.
Besides, using a modification of d20 means I can steal ruthlessly from existing content rather than creating every option from scratch, and players will be mostly familiar with it.