So instead of trying to reconcile several different types of song under one label, can't we just say that we may loosely call any narrative song a "ballad", but within "ballads" there is an important sub-set, which we might call "Childean" or "Border" (to meet English and Scottish half-way), and (if you are unable to identify them by how they sound and how they affect you) these ballads are easily identified by provenance and by certain technical features.

Therefore, yes, "Leader of the pack" is a sort of ballad (if you should choose to listen to such garbage with a straight face). A "pop ballad", perhaps, whose main purpose was to make some recording exec a pile of cash.

Or is that a bit too simple and grown-up for you all?