1. The coach should share just as much blame for vetos going wrong. In fact they should arguably be blamed more. They're the ones who should be responsible for establishing their team's map pool and tactics. The IGL should just be the one making mid round calls.
2. It's hardly fair to blame an IGL for choking once in a fight against the world's best player. If Guardian/Olof/Rain/Niko actually showed up then mistakes like that wouldn't matter. Besides, i've seen countless scenarios where Karrigan has actually clutched hard against much more skilled players. He's one of the best IGLs for that.