I kinda like Tactic's take on gambling- instead of simply risking caps in casinos, you can put up items for stake and risk them for equivalent items from random NPCs in the Wastes. For example, I might bid two Stim Packs for a clip of ammunition from an NPC that accepts gambling. We play a dice minigame or something, and whoever wins takes the whole pot. It adds a lot of depth to the gambling system as a whole because players become forced to risk more than money if they always want to get what they want.
I like this way as well but if the cap for every casino is $2000 you will run into "to rich for my blood." I hated that in FO Tactics. I don't have the money but I have items but the items are worth more then they have to gamble.
If the cap was $100,000 or more it would make things more interesting. Playing a game of poker and you don't have enough to bet and you have a Straight flush, don't have the money but you have a nice plasma rifle

. Would make it so you have more to lose then just money. Would be awesome if they could make it so the other people you are playing against could say "what else you got?"