So performance tools are fine, as long as they are hard to find (=not user-facing)? And the percentage of users that would want them has to live with worse access to them to not scare the others with an extra menu entry?

Yes.

The more commonly used features are, the more prominent they should be in the UI.

If not, the "Compose" or "Send" button in email clients should be as big as "view connection details" (to give you an example).

That's how you reduce clutter. GIMP does that horribly, so they should probably _remove_ something, not add.

The Dashboard dock is user-facing only if the user chooses is to be user-facing.

Come on, get a grip on yourself.