I am sure I am not the only one that was excited when they first talked about being able to fly to other cities, but then after flying for hours you get there and you are locked in the airport with nothing but a gift shop. I really think there is a lot that could be added here and that is what I want to suggest. None of my ideas will be perfect or set it stone. Just me tossing stuff out in hopes someone likes it and puts some of it into the game. I would be happy with almost any change to the flying system we have now. Sorry no images, might add some later but mostly just want staff to run with it.
In short I think every city should have almost every thing torn has but different... maybe better depending on where. Having the option to fly to other cities would be good. Maybe torn is the only one with access to all. Every city would need it's own item page and then you could pack and unpack what you want to take or leave. Maybe city trading where some sell goods for less and others buy it for more. With prices changing as supply and demand changes. I don't think this should be much more than a few mil pre trip if that. We are using suit cases not cargo planes.
Switzerland aka rehab, should jail you for bringing in drugs with a low chance of getting to keep them with no jail time. So in short you would only be able to use drugs that you can buy there or pay extra to use other drugs smuggled in.
Flowers/plushies might have to limit or not allow you to store them any where other than torn. Thinking same with not letting empty boxes or gifts be packed into a suit case.
Crimes, some could be the same but with a few small changes to fit the local area better. A few new crimes that are only in that city.
Gyms, we have a huge list of gyms but we only really have one that we use. Some times you might switch to one to work on your highest stat but for the most part not really used. Maybe we could move some or unlock new gyms for areas.
Houses, why not let us buy houses unique to the area. I don't think we need a huge list but do need some price ranges. I think starter house could be a crappy hotel. With some of the better houses being an apartment in a high rise building. Your happy would be based on the house you own there. It would need to be it's own happy or it would mess up your happy when you fly for flowers and don't own a house there yet.
Faction city, I think it would be cool if some factions had control of other cities. About like territories or maybe just territories. Torn's would have to be changed though so this might not happen as that was just added. I think just making the blocks not as tiny would be a fast fix.
Faction location, the place your OC's are based in. I think a lot could be done here to make it worth the move. All OC's would have to be stopped to move and moving the faction does not travel the members. They all have to fly there on their own. Same with personal crimes some are the same but with the local stuff added and a few new crimes.
Faction wars, I don't think this will break the war system but it might. Only thing that might help is showing what country the members are in and not just traveling. You will need teams of guys around the world to chain if factions are not based in torn that you want to war. I don't think wars can be limited to one city as it just wont work. Not being able to move locations if you are in a war might mean you never move for some factions. Also kind of on that note can we make it so one man factions can't go to war on other factions?