Well, I doubt any minecraft accounts will be threatened to get stolen (besides big names like CaptainSparklez).
The thing with Heartbleed is that it's mostly focused on bank accounts, BTC, and PayPal.
I wouldn't be too worried if you're just an average user, however if you have a very high profile bank account with a handsome amount of wealth in it, I would change your passwords.
It also focuses on messages sent in the deep web. Business information and critical government information. The crime of stealing documents about tesla production.. god I wonder how fast you'd be put on death row.
Another thing to keep note of, this heartbleed bug has been around for a while, and it just got fixed yesterday. However, keep in mind some web services can still be using an old version of OpenSSL... I'd recommend you keep a different password for different services. Rest assured, most surface web services should be upgraded.