Fnatic went to semis and C9 were in the same team

So 2015 Fnatic wasn't top 4?

the Korean team of group A got second. And CLG couldn't beat the Flash Wolves

Are you arguing against yourself? Which is it, Koo weren't actually good because they got 2nd, or FW didn't actually deserve to be 1st in the group? If it's the former, that means Fnatic were trash since they got 3-0'd by a team that lost to a team that Origen smashed. If it's the latter, Origen had the easiest possible QF matchup and were exposed once they went up against a genuinely good team.

TSM could've beaten Origen to get the same "easy quarters", instead they lost to them 0-2.

I'm not arguing 2015 TSM was good. NA was objectively shit in 2015. That's why it's not impressive that Fnatic and OG beat NA teams in groups - if anything that only serves to prove my point that they were lucky in the group draws. If 2015 C9 and TSM are some of your toughest competition, you'd didn't have tough competition. We're not talking about single years though, we're talking about the history of the two regions.