I would say no to both of these.

Regarding the voting to fill vacancies - if a vacancy happens during a crucial part of the season it may not be in the best interest of the club to have to take the time to go through a formal voting process.

Regarding the term limits AND the voting to fill vacancies - the majority of the elections are for candidates running unopposed. The fact is that there simply isn't a large number of people even WILLING to serve their club. If someone can get elected for a fourth term or is willing to be appointed, let them serve!