Majors is a CS term describing Valve hosted events of significance, hence Blast Premier and other third party torunaments are not considered majors.
All the main circuit tournments are and have been run fully by riot starting with first strike so this term makes no sense because I think most people would agree that first strike and masters 1 were signficant and run by riot but are not 'majors'.
Aka the term doesnt make sense because then you get into the 'was lock/in a major' bullshit when in reality it was essentially just a masters with a different format, taking up the normal masters slot, having the same prizepool and teams treated it as such.
Champs > masters = lockin > regional riot events like masters 1 and splits >third party tournaments such as redbull homeground.
ditch the term for the love of god its just useless in this game.