I'll start by saying that I expect Moose to be ubiquitous. If it's not now, it will be.
Moose has a huge loading time that makes it unsuitable for many tasks.
On my (somewhat old) computer...
$ time perl -e 'package foo; use Moose'
real 0m1.052s
user 0m0.880s
sys 0m0.044s
$ time perl -e 'package foo'
real 0m0.008s
user 0m0.000s
sys 0m0.008s
I see no problem using Moose inside big long lived applications or frameworks like Catalyst and alike. But using it in a generic CPAN module unnecessarily limits where that module can be used.
BTW...
$ time perl -e 'package foo; use Params::Validate'
real 0m0.066s
user 0m0.028s
sys 0m0.008s