I mean we already have stuff like loaded dice as a base option. I actually like the way other games have it though, where, for example, you have core rules, easy/story mode, and hard or unfair weighted in favor of the AI. This is how Wrath of the Righteous and Kingmaker did it.
As for party size, it's probably limited because of multiplayer. They likely don't want groups of six players in the same game. Why? Who knows. But multiplayer is the primary reason for a lot of design choices in games.