That puts us right back in the "ruler changes religion but now has to convince the nation" boat though. Powerful group taking control of the government amounts to the same concept.It's still absurd, no matter how you slice it. Conversion via rebels *should* be a powerful religious group taking control of the government, not 3000 guys from a small village somehow occupying an entire empire while the army of the current regime sits and watches.
We get weird player behaviors because the game rules/incentives don't align.