Mantha came into this year with the expectation that he could possibly step right into the NHL and perform. He was also protected by management in trades as an untouchable.
Yet he didn't make the NHL, and was average at best in the minors, often appearing as if he was just coasting.
Sure hes at the same point as Nyquist and Tatar in his career, but the later two exceeded the expectations the team had for them, not the other way around.
I think the public criticism is well warranted. This isn't a boom or bust prospect that is faltering. It's a blue chip vastly underperforming. I hope it lights a fire under his butt for this summer and next year.