Well NIKo having a history as IGl matters, a lot in fact. Because he obviously has a vision of how the game is supposed to be played. On teams with a clear IGl like Astralis a player like BlameF can assist calls and i mean he even calls on Mirage even though he isn't the IGL.
G2 probably suffered because of NIKo's history. In the most important rounds in the game, if things didn't go the way G2 wanted, you can almost hear NIKo say "We should have done what i said".
That's gonna create a lot of tension. Now imagine having three IGL on the same team. EG had this exact issue except it was between IGL and Coach. It doesn't matter that they only did for a short period of time, that fact will always remain. Same story with Magisk standing-in as IGl for Astralis, he now has influence in Vitality (Probably).
Also consider that CPHF is basically a nobody org. Outside of like a 6 month glory period they are nothing. They have a small whatever fortnite divison and that's it. Tiny org with limited budget and reach. Sprout and no giant but they have a name in LOL and PUBG + look at the players they are signing. Multiple ex-tier 1 players with a lot of promise.
Better org + better players + no role clashes. You can't seriously tell me that it's not even possible that they might reconsider