CPAN dependency resolution seems worse than with other package managers for two reasons. First, CPAN prefers to install the most recent version of a dependency (rather than pinning to a specific version). Second, the default CPAN client behavior is to run the entire automated test suite for every distribution it installs.

While that behavior feeds back into improved quality for responsive maintainers, it takes additional time during installation. When combined with point #1, it can make dependency chains seem more fragile.