While I favor term limits, I understand why politicians aren't willing to cut their own throats by imposing term limits. Politicians won't do anything that may reduce their power, their money, their security, even if that is what the majority of the public wants. Politicians will have to be FORCED INTO imposing term limits and making other reforms.
I would favor something that says no politician can hold any more than two elective offices of any kind. Also, after leaving office, they couldn't use their former political position for any kind of financial gain for ten years after they leave office. That would include selling books, lecture tours, being a lobbyist or earning any money as a result of their former political position.
They wouldn't be prohibited from writing books, giving lectures, or doing other things, they just couldn't get money for it. If they want to give free lectures, they could still do so, that would avoid them saying their first amendment rights were restricted.
But I'm not king, and politicians won't vote any of these things into law.