- Rabiot: very tempting on a Bosman and would be a decent signing under Fergie, not sure the club's current organisation is robust enough to properly handle him, though — the potential for headaches probably outweighs his ability.
- Kroos: most gifted German midfielder of the last 20 years with Gündogan but he doesn't have the hardy mentality of someone like Schweinsteiger, and leaving Madrid after winning multiple European Cups might lower his motivation even further, especially considering he's also won a World Cup ad a bunch of titles at Bayern. To add, he's another player who's not the best fit with Pogba unless the third midfielder has peak Vidal/Kanté level workrate.
- Wan-Bissaka: Dalot is an elite fullback prospect and could develop into the type of 10+ assist player we've lacked in that position, no need to sign someone of a similar age profile.
- Maguire: worse pure defender than Smalling and bit clunky, and not astute enough in possession to offset those drawbacks.
- Coutinho: too much of a selfish maverick at times, and his decision-making is suspect — don't think he will be a good fit with Pogba either.
For me there are 2 inter-linked issues with Wan-Bissaka (who is a good player, just not someone we need, IMO). First has been outlined already, sort of: we have Dalot, who's a very gifted player at the position from an offensive sense and has a rare knack for delivering sumptuous deliveries into the box, but somewhat inexperienced — he's not going to gain the experience needed to hit higher levels if you sign someone who is only 2 years older and will act as an impediment. Second: most elite clubs these days has at least one fullback that is a consistent threat in attack and can hit a peak of 10+ assists (think along the lines of Marcelo, Alba, Carvajal, Kimmich) and a potential combo of Shaw and Wan-Bissaka would not be a step in the right direction in that regard. Dalot, on the other hand, is definitely someone who can reach those heights if he's developed properly and needs a patient approach — too much is made of his lack of elite defensive awareness when top modern fullbacks improve in that regard only with age/maturity — and he's actually further along in his development than the likes of Cancelo (excelling at Juventus and arguably a Top 3 rightback in club football), Semedo (doing quite well at Barcelona), Pereira (one of the better Premier League signings of the season) at 19.