I agree with you that pragmas are a very reliable dependency.

But (for groups of humans) simple rules are usually better!

Encouraging a "my module has less dependencies then your module" race is dangerous in my eyes, as long as it's based on interpretations of such fuzzy definitions

Don't you think it would be better, if everybody was listing every used module / pragma, and CPAN and/or MetaCPAN or whatever provides an objective metric (a number) or graph?¹

Edit:

At the very least active core modules could be automatically filtered of such a tool.

The dependency tree at CPAN already marks core dependencies, maybe this has just to be graphically enhanced.

Update

Practical suggestion:

Here a dependency tree of Moose linked from CPAN.

Hiding non-deprecated core-dependencies by default and adding a button Show core modules shouldn't be too difficult.

(BTW: Plz note that Moose lists warnings but not strict ;)

¹)<meditation> Possibly based on:

• deprecation
• age in Core
• age in CPAN
• last update
• open bugs

</meditation>