Personally I found the civil wars alsightly wearing. They were so devastating to an empire that I employed draconian tactics to keep them in line - either buried in a loyal stack, with the heir or utterly alone to lower the effect they could have. Really rebellious ones had a tendancy to die in battles. So as suhc I don't think that is was that great a feature.

Do the rebels "think" as a faction, or is it a convenient shell to dump them all? Having them acting at least partly in concert would IMO be a nice change.