I think there is a good model in (for instance) the UN Committee on the Rights of the Child. Committee members are allowed a certain number of terms, three I think, of limited time each (again I think three years) after which they must be replaced. The membership was originally staggered so that each year the permissible re-elections or replacements were possibe. Thus a part of the committee is replaced every year and stagnation tends to be avoided by having a permanent and increasingly conservative membership. Also chairs have a term of office and only a certain term as chair allowed, which means they cannot come in as a chair on the first year and effectively require several years to get there, thus accruing experience. There is also more than one deputy chair so that chairing is not thrown off by non-availability. I recommend people take a look at that Committee and similar and begin to take it from there. I have been on lots of committees, been in local government office, a charity trustee and so on so have seen the direst messes as well. The UN model is pretty good compared to many others and easily adaptable. Discussion would be good.