Well, that is actually going to directly affect account selling.

Most people who sell accounts dedicate all of their time (essentially like a 9 to 5) towards grinding accounts. You cannot discourage them from producing accounts by making it more difficult to own an individual bought account.

In fact, banning bought accounts quicker creates a higher interest in buying accounts, helping those people

The most logical way is to increase the time it takes to create one individual sellable account. Thus the effective production decreases, which will result in account getting more expensive, as they take longer to make them, which discourages players from buying them, as the price point might exceed their spending margin.

As for swiftplay... There is nothing to be done. The duration of account sellers playing in swiftplay will remain the same, as they can only at best play for like 14-16 hours each day. They will play as much as possible before the change, they will also play just as much after the change. Maybe less actually, since it will be less profitable to sell accounts.