In countries where a minority sect is in power ruling the majority sect the revolution has not succeeded (yet) and the repression was most brutal (Syria and Bahrain) .
Countries that are homogeneous and the ruling elite and army are of the same sect as the majority of the people, the revolution succeeded (Tunis and Egypt)
Yemen , the Zaidi/Shaf'i exists, Zaidis (shia) are in power but they are not an overwhelming majority,and the sectarianism is not as extreme so the revolution is succeeding slowly. Interestingly the Houthis (shia 12ers) who fought Saleh for years have been awfully quite since the start of the Yemeni revolution.
Libya is the exception since it went through a brutal civil war and NATO intervention despite it being homogenous sect wise.