I think something else that could be a factor in people quitting on the kage, is that it's losing it's charm being the 10th+ kage in a village. We're at 15th Kazekage now, and most of the players currently, have no clue who the first 7 even were
Although, I don't agree with some of your points, since each village is run and build differently (e.g. monarchy, anarchy). So not all the villages are gonna be popular just off that reason alone. One option, could be a mid-term election. So after 3 months, you can decide if you wanna do the full 6 or stop your term there. Idk...