I agree that Perl 5's exception system is somewhat clumsy, and makes it hard to filter by exception type.

On the other hand, in my mostly small, mostly fun projects I haven't needed that feature at all - either I just hand on exceptions, or drop them, or warn and continue - so far I always left the interpretation of the error to the user, which worked pretty well for me.

That said in Perl 6 we will have something like an exception hierarchy (except that it won't be exactly tree like, because we don't just rely on inheritance but also on role composition). But the problem - as always - is that somebody needs to actually do it: define a structure, default error messages and so on, and spec that.

So please take this as a call for volunteers. If you are (like me) interested in Perl 6 having a better exception system than Perl 5 (and one that makes translations to other languages easy without breaking any code), consider contributing.

(I'm glad to help where I can, but I won't be the driving force - I have too many other Perl 6 related projects I'm working on).