The Gen.G vs T1 and KT vs IG examples show exactly that it IS on the tournament format to salvage the situation. Since there is a time gap between the regionals and groups in which the meta changes and since many teams wind up to be better and better coming from groups to playoffs, there will inevitably be seeding errors that can "ruin" the tournament. It is way better to change the the format than to hope that seeding from regionals into groups and from groups into quarters will just turn out good. The current tournament format just isn't robust enough to account for possible (and arguably very probable) errors in seeding. The double round robin bo1 groups and single elim playoffs is the probably least robust tournament format ever with no methods for internal correction of lopsided groups and bracket matchups.
But how could you possibly fix them? Outside of just saying “nah actually T1 is better we are going to overwrite your seeding” you’re going to get misshapen groups unless the regions seed better. Similar is seeding a 1st place group team vs. 2nd. What, we just say “yeah don’t care, IG is still top seed”? The tournament has to play out.
Playing 2-3x as many games is not the solve for that.