What is really important is for them to stop making it easy for every new virus to spread by hiding file extensions by default! The FIRT THING every intelligent person I know does, when building a new PC, is to go in to settings and turn on the ability to see file extensions. Those who remember the Anna Kournikova virus know how long this has been an issue, and MS still refuses to fix it.
Marketing and Development: "Should we fix these security flaws, or add more spyware to the OS? Spyware of course, nobody cares about our stupid customers!"
Technical it's not a security flaw. What you said implies that the spyware virus is using a bug to do it's thing but it's not so there is nothing to "fix".
What you really mean is they should change the default so that less tech savvy users who click anything put in front of them might possibly see the extension and know the difference between something that looks like an image/video file versus one that is an executable.