I really think the IDS has the best regional election system when it comes to Class A/B. It forces individuals, parties and movements to be active and participate in democracy every month, rather than every two months. It also means that if you want to control a majority of the legislature, then you have to wage electoral battle each month (and win 2 out of 3 in the Class A elections). The other regions should adopt our approach.
No one element helps guarantee activity or competition, but I think the 3/2 cycle is the better method for those aforementioned variables when combined with other elements.