Complete knee jerk to yesterdays game. Maguire is going through a shit spell its true, but he was solid for us all of last year - and as importantly was actually able to stay fit and give us some sort of stability in our back line. Ditto AWB.
I would argue that he actually made very little difference to our defence. When you include the signing of Wan Bissaka, the decrease in concession rate from the season before was marginal. I seem to remember that we would concede 6 fewer goals than the previous season when you took into account the first half of the season's form).
It wasn't until we signed Fernandes and brought in Matic that our defensive record improved dramatically, not when we signed Maguire. When Maguire joined, we conceded in every PL game for three to four months (from September, I think it was, mid-December; it was a long time either way). It begs the question: did our defence improve at all? Also, was the main issue actually not having a proper AM that allowed us to pin the opposition in their half? Put Smalling in his place, and I think we would have ended up with the same results last season.
Overall, I think Maguire has been a poor signing that may go down as one of our worst (arguably, the worst) in history.
James was a punt that hasn't worked out, so I am not too bothered. He is clearly not good enough, though.
I still think Wan Bissaka is a very useful player to have. One-on-one defending, he is arguably the best in the league, but his attacking play can be dodgy, but he did improve. I like him myself.
Fernandes has been a good signing. Too much of an overreliance on him, though.