My friend and I thought about a a little change in Minecraft usernames registration that will help with 3 different things: Less accounts will be stolen, If someone get the user name and password he still can't play with the account, a lot less hackers in servers.
1. Each account must have at least one security question.
2. You must use answer your security question when you log in you Minecraft account in your Minecraft Launcher.
So how less accounts will be stolen? People will need to have at least one of the security question and use the account, so even if you have the details of the account you can't play with it, and because of that, less people will hack, and that's because people usually hack with alt accounts, and people usually hack in stolen accounts.
I'm pretty sure most people lose accounts in general, not just in Minecraft, by giving their information to sites that seem legit or people who claim to be admins or something, not necessarily through someone breaking into their computer. Adding more information you need to log in won't fix people handing over that information and it won't stop all the accounts that have already been stolen