Leicester have won praise for the Maguire deal after the 27-year-old's patchy form since Project Restart.
An offseason incident in Greece, which saw Maguire arrested by authorities, has been compounded by a number of poor performances both for United and England.
United fans are hoping Maguire will improve, but Piper doubts if the England international would be willing to work on his weaknesses.
"To be a top centre-back you've got to be good in the air, quick across the ground and it helps if you can play with both feet. (Maguire) being so right-footed hinders him a lot. Even in defending because he doesn't even go for tackles with his left-foot. He jabs at it with the outside of his right-foot and he's too easy to beat.
"Does he want to get out and start using his left-foot and start trying to start re-engage with the development side of his game, I don't know if he does, I don't know how many top level players who want to do that."
The Foxes have sold a number of star players in recent seasons, but have still managed to stay competitive amongst the Premier League's 'big six'.
Despite losing Maguire in the summer of 2019, the Foxes spent most of last season in the top-four and eventually finished in fifth.
Brendan Rodgers' side look set to once again challenge the status quo in English football, and Piper thinks the club's recruitment deserves praise.
"That's why Leicester and their recruitment and decision making of when to sell players (is great), I think they've only got one drastically wrong in recent times and that was (N'Golo) Kante, but that was only because the clause was already in his contract when he went to Chelsea. The Maguire deal was unbelievable for the skillset of the player.
Matt Piper's autobiography, Out of the Darkness, is out now on Pitch Publishing, which you can purchase here.