Those kind of leaders are much better at getting the most out of teams with mediocre firepower/skill. When you try and micromanage a team of highly skilled stars all you're really doing is watering down their skill.
FaZe just need an IGL who can make smart calls, which Flusha is more than capable of. And more importantly, given the egos on the team it needs to be someone they respect and have confidence in. There's no way NiKo would follow a loser like MSL.