Hard to say, I liked FNS's calling better for his shorter time of dominance (Optic days he was IGLing with innovation not seen yet, Saadhak should be mentioned here for that too) but Boaster has consistently had some variance in his roster and his teams have been top tier most years.
However, that talent has seemed INSANE, so how much is it his calling vs. his players is still a question to me fs.
Also, where does the coach come into this equation, its not always obvious on whether the coach's instructions lead to proper calling/wins/strategy or if it is the IGLs. There are closer to obvious observations like midrounding/reads, but what to do with that could be either. 'Having the read' is pretty much all in the lobby, IGL or players, but what you do with that read could be drilled/from org, or from IGL or both.
TLDR: Basically, hard to tell their impact without having full team context.