Shitty formatting was the only issue with kickoff.
Kickoff also gave circuit points and was a qual event for masters. It fits every theoretical bill for an S tier. I dont see it as an S tier, but on paper it counts as one.
Just like cs fans say, some majors aren't S tier because of the lack of competition, however the general rule is that the event itself, is due to level of competition and scale of the event. PGL Astana for example.
However like you said, CS is a different ecosystem. It doesn't have a version of "worlds/champions", and only has majors. However each major has it's own prestige behind it.
Also by your definition kickoff and stages are S tier. Hosted events, offline, by riot, part of the vct tour?
I'm also not saying liquipedia is the definitive answer for every event. I'm saying their rules on their rankings is the general consensus of what makes an S tier. They also said lockin is S tier, and I honestly believe that was A at most. They're not 100% right with some tournament tiers, but it's usually based on who's attending. you're seeing the best of the best, with S tier teams facing against each other, on a grand stage. It's not the best way we have to describe metrics, but it's the only loose definition that most esport scenes go by.