Go back to the classic ranks. 
Reset everyone to bronze 1. 
Remove anything below Bronze tier(Trainee & Green). 
Convert Green servers to bronze/silver. 
Give rewards for ranking up per tier. (once per character) 
Give increased rewards for playing in your threat district. (day of premium, guns for a couple days, mods for guns, character, cars) 
Add things for max level players.(map, contacts, missions, etc).