To be fair to Maguire, a lot of this is self-inflicted. His media and off-pitch demeanour are just as damaging as his tragic performances. With him, you can clearly see an entitlement and a refusal to own your own mistakes. The fact that he's a captain obviously amplifies all of that.
At the end of the day, the fans just don't want to see their team led by guy who has clearly crumbled under the pressure and is at the point of no return.
The biggest favour that the manager can do to him is to take away the armband and take away some of the focus on him. He will still be the 80m flop, but at least he won't be expected to be the guy that has to apologise after every shameful loss. Nevermind that it will be far easier to rightfully drop him.