A guild like that is just a leveling farm, leave it as it is and people will continue to invite new toons and alts to benefit from all the perks and they will leave to find a better guild. If you are trying to change things, then reward the 85's who are on with promotions, gold, and bank access. Guilds like this run themselves. If there are 10 people who want to raid, they will set it up themselves.