The line of "major" is arbitrary, and changes per person. It's basically useless information to everyone but the person/people actually making the version change. Having it there can just lead to anger when something that you would consider "major" doesn't make the cut, or when the "major" bump doesn't have anything you care about.
Semver is in no way the end-all-be-all of versioning schemes, but at least it's pretty objective for the most part in the sense that it can prevent bikeshedding about version numbers, while still giving some useful information to the users.
That being said, I'd love a system that lets me view changelogs by the version "level" I want. So I can easily lookup the major changes since v6.6, and someone else can check what has change since v4.2, etc... With Semver a lot of my time is spent reviewing every changelog between my current version and the one i'm bumping to, and there's no reason it needs to be that way.