package is a reserved word, so I won't use that. Second, this module only works for classes. It doesn't work for non-OO stuff. The reason is pretty straight-forward. To make it work for a procedural module, the syntax would be like this (picking "aliasing.pm" as a nice alternative):

use aliasing "Really::Long::Package::Name";
print Name::some_func();
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In order to get that to work, I need to alias typeglobs together like namespace does. However, by literally pulling things from one namespace to another, I would break a lot of code that is expecting a particular namespace (whether or not it should is an argument for someone else.) Thus, the principle of least surprise tells me that I need this to work only for classes and I do this by simply providing a subroutine that returns the original class name.

Further, from my experience with code that's very similar to this, packages with long names are either procedural code that exports what I need (hence I don't usually use the package name after the first usage) or classes for which the aliasing code makes sense. I don't typically find cases where I need to do this:

my $foo = Really::Long::Package::Name::some_func();

Of course, your mileage may vary.