Well it's been done all of these ways and more...

Life is messy, isn't it?

[that's a rhetorical question. I agree that there should be some system to how songs are titled or categorized. As to the 'principal burden of the song as a whole, I don't even know what that means... Is the burden the same as the riff ?]

Be that as it may, people have been doing their own thing when it comes to naming songs, and they are gonna keep on doing their own thing and there's probably nothing we can do about it but comment and then keep on keeping on.