That's a fair point, but strats alone aren't what make Astralis so strong. The way they are able to execute them so perfectly and adapt to what's happening in the round is what makes them so dominant (outside of their individual skills of course). And I don't think that would be possible without able IGL. And when it comes to mid round calls it's kinda logical, that the people with the most info, that is entry and sniper, are making fast calls depending on the situation. But the overall gameplan lies in the hands of IGL.