I think drugs should be left alone, but maybe they should add new legal ways of making money. The whole north side of the map is basically empty and has plenty of space for an addition.
Some Ideas
Fix Hunting and expand it throughout the whole north side of the map. Some animals legal to hunt, some illegal. If found with animal meat and no hunting license you are subject to search seizure / charging?
Ability to mass produce market items. ex. 4 x Redgull = 1 Sugar? 1 Water Sells at full market price
Ability to make clothing at clothing factory? ex. Carrier Lite = 4 kevlar, 6 Cloth. Option to sell / keep
Making these items might not affect the number that are on the market, but it would definitely be a cool addition.