Bank robbing: Bank robbing is a really cool idea but I feel it's useless right now. IMHO it would be cooler to make a large amount of money from robbing the bank, upwards of $25k or so, but make it very hard to do. Make a HUD message appear for all players, "Bank robbery completion" or something and it goes from 0% to 100% over the course of 5 minutes. The bank robber has to stay inside the bank the whole time, and if he dies, it is failed, but if he survives the whole 5 minutes of CT's trying to kill him, he can flee. But the robber would not be able to use any bank services for 2-3 minutes at least to prevent him automatically depositing the money.
^ This would just make it extremely hard to rob the bank successfully but a lot of fun/value in trying to.
Gangster NPC: Would be really cool to have an actual system for gangs and gang wars. You could create a gang for something like $100k-$200k, and invite people to your gang whenever you want. Gang members kill rival gang members on sight, not considered RDM. Would be awesome to be able to choose a 3-letter tag or something for your gang that every member automatically gets put in front of their name instead of the "drug dealer" tag (or w/e job you have).
It could get really fun and in-depth, such as you get awarded $100 for everyone you kill who's in a gang but not yours, setting up gang houses, etc.
Getting rid of the market NPC for a cool economy:
I think this would be a really cool legal way to make money and kind of create a little bit more of an economy between players.
New job: FARMER. The NPC in the market would no longer sell food items, but they would sell seeds and things to GENERATE food. Only the farmer job could use the NPC, and you could plant things like Potatoes and other vegetables in your house. The market NPC would sell the seeds to plant food, it could sell Chickens which generate eggs, etc. And then instead of selling those to an NPC itself, you would sell them to other players only. The only way to get food to heal yourself would be to buy it through a farmer or someone who had them in their inventory from previous farming.
