Perhaps there should be a way for this module to gracefully age....
That would be silly. Either a Perl version is modern or it's not. 5.10 is modern. 5.8.x is not.
Perhaps you mean a version of Perl is 'current' or not.
Well, that's what I'm trying to get at. Modern is relative. A particular version of perl (and associated features) is not.
What is modern changes with time. Just think clothing styles... bell bottoms were modern at one time (1970). The time is fixed. Bell bottoms as being modern is not.
Likewise, the features that you currently deem 'modern' are only modern in our eyes now. There is no doubt about what features you see as avant-garde, best practices, etc. But that is a pick for this time and this version of perl.