I took RM2, houseruled it until it was pretty much the game I wanted, and then skipped RMSS and RMFRP entirely.
And from what I've seen on the ICE forums, I suspect that my answer was the rule rather than the exception. Because of that, the publishers had a major problem in that it had "splintered" so badly that it was nearly impossible to make anything acceptable to a majority of their fanbase.
Or at least that's my understanding. I certainly could be wrong about that, it wouldn't be the first time and won't be the last.