IMO at the moment it is not worth doing it. For those who want to protect their servers, there are paid solutions that do their job decently. This is harsh, but if you can't afford, it's not developers' fault.
Most vulnerabilities can't be closed efficiently if you don't protect the game client too. It's not our job to fix Gravity's client.
If there ever will be a decent opensource RO client, then we should reconsider providing security measures in conjunction with said client.