The two year half spill model should definitely go. From a team dynamics point of view, these people have to getvised to and become effective again every two years. An effective team can take a while to spin up, especially in a role where most people coming into it have had little or no experience in that kind of role before.

Thats not even to mention the game playing and politicking, such as trying to wait out the clock on council members before decisions are made.