Java deals with this by refusing to import any classes which conflict with other classes. Perl's dynamic nature makes this rather difficult to guarantee. This is particularly troublesome because authors might dynamically build a class at runtime, populate the namespace but not add an entry to %INC, thus causing mysterious bugs when only an %INC entry is relied upon when you actually need to check for the existence of a given namespace.
I can work around some of this, but some of it would be in the hands of a programmer to be careful. I think this is the biggest drawback to this module. However, the question is whether or not this will prove to be a prevalent problem in practice, as opposed to theory. I've seen people refuse to use code whose philosophy they theoretically disagree with even when the reality is far less problematic than it's made out to be.