Wow! 50 replies to my lowly thread. Don't you just love when a topic takes off. Anyway thanks to everyone for all the response on this idea. Hopefully together we can get MM to implement this. Now back to business
Mac your idea sounds a lot like Trachmyr's with one world triggering the rebellion and thus influencing the others around it (read his post below).
This idea (one small rebellion instigating one BIG one a.k.a. Civil War) could be another trigger. Along with the loss of the regional or galactic capital, we now have two triggers

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What could be some other triggers? or rules for revolting planets?