A few more things:
1. Actually this only happened to me with Byzantion - other cities revolted with no problem - I just reconquered them. So it has to do with thic particular city - may be with its past affiliation or building built there... (or not built there).
2. I wanted to ask you if it is a normal behavior to have in certain cities "Regional Pacification" being built for more than 40 turns... and until it is completed nothing else can be built, and as a result unhappiness increases overtime - population grows, but now happiness building are being built...
Thanks.