I know that DLC in the form of maps is not gonna happen. But I was wondering, how about adding new content to purchase from the in-game store?
There will be a point in the game where you will have bought everything from the store and the amount of money you have will keep increasing since you have nothing more to buy. They should release other things that we can purchase in the in-game store with the in-game currency.
Things that only last for a certain period of time. That way, you could keep buying them and spending your money. And they wouldn't be cheap, either, so that you would have a point to keep spending money. I think new achievements would be good, they wouldn't be overly hard to add and would extend the replay value. Maybe new ranks to reach, but make them really expensive.
An interesting idea: there's a certain number of credits that need to be put in the "melting pot" before the next update (not patch) will happen. It's a ridiculously huge number, so people who have quickly accrued a lot of credits will have to spend them. If people meet the number of credits within a time period, anyone who contributed over a certain amount of credits will receive an exclusive item that they can show off.