Sure, he had a ton of talent around him, but I don't think that's the only thing that matters. The TSM/Astralis lineup that he had still had their choking issue, which didn't fully get solved until Astralis brought in a psychologist. I'm not sure the exact timeline of when they brought the psychologist in, but given he was out of the team months before there was any press about it, I'm guessing he didn't get to reap too much of the reward. Given how good TSM were at $50k events in 2015, I can't imagine how good they could have been if Dev1ce had been able to perform past a quarter final at a $250k event.
FaZe is a bit weird, but putting together what information we have it seems as though his leadership was short circuited by NiKo at some point. No matter how much you try, your position as an IGL is meaningless if your superstar player won't listen. Now maybe I'm reading too much into things, but given FaZe never picked up an established IGL again despite several being available tell me that maybe NiKo didn't want one for whatever reason.
I don't think he's the GOAT, but I think that's only because Gla1ve exists