Diversity of tactics

One of the problems with several RPGs and strategy/tactics games that I've played is that the game enables me to fall back on the same combat tactics, or perhaps the same spells, time and time again.

It would be interesting to have an RPG game that forces you to do different quests with different party configurations / different characters, forcing the player to make the most of the tools they are given. And forcing them to explore all of the content.

A possible theme to accommodate this:

You control a transnational organisation of spies geographically dispersed around the world. Missions become available in a particular geography, that can only be done by the agents in that geography, so the player can't keep relying on their favorite character. The player can move their agents between geographies, but the cost is generally prohibitive.