A remotely exploitable hole in bash

Not sure what you're arguing... Don't you remember all the breakage reports caused by the devfs removal? And Greg KH's unapologetic emails? (IMO rightfully so, good times) If not, no big deal, there are other user-visible deprecations to be found in feature-removal-schedule.txt.

Linux's backward compatibility is nothing short of stellar. It's part of what makes using Linux such a pleasure. But, on the rare occasion that a mistake is made, we don't have to live with it forever. It can be fixed.