1st half of last season:
Rashford--Martial--James
Pereira
Fred----McTominay
Shaw--Maguire--Lindelof--AWB
DDG
Strengths: our pace on the counterattack
Weaknesses: no width, susceptible to high pressing, inability to break down deep teams through the middle
Tactics most often used against us: keep it narrow, play a deepline, and hit us on the break
Post-Bruno pre-lockdown
Rashford--Martial--Greenwood
Bruno
Fred----McTominay
Shaw--Maguire--Lindelof--AWB
DDG
Strengths: our pace on the counterattack, Bruno's quick passing to breakdown deep teams through the middle
Weaknesses: no width, susceptible to high pressing
Tactics most often used against us: keep it narrow, play a deepline, press AWB and hit us on the break
Post-lockdown
Rashford--Martial--Greenwood
Bruno
Matic----Pogba
Shaw--Maguire--Lindelof--AWB
DDG
Strengths: our pace on the counterattack, Bruno's quick passing to breakdown deep teams
Weaknesses: no width, extremely susceptible to high pressing
Tactics most often used against us: keep it narrow, play a deepline, press AWB and Pogba, and hit us on the break
How do you fix it?
Imo,
1. Set up a backline/midfield that can make easy but unpredictable transitions out from defence
2. Give our players who lack press-resistance more options when they're on the ball
3. Try and create more width
4. Retain Bruno's central importance
5. Retain our pace in attack
So...
Rashford--Martial
Pogba---Bruno---VdB
(Telles)-------------------------------Williams
Shaw----Maguire---McT
DDG
Shaw and McTominay aren't natural centrebacks, but both have played in back 3s before so there is some precedent.
If we set up like Wilder's Sheffield United do with their overlapping centrebacks, we should be able to solve the problem of getting pressed to death. Both are decent passers, both are good at carrying the ball, both are aggressive defenders who are good one-on-one, both have the body-strength to avoid getting pushed easily off the ball. What they'll lack in old-school positional discipline, they'll hopefully be able to make up for in numbers.
The midfield gets shored up with extra creativity. Yes, we lose one attacker. But I think we gain more from having all our best midfielders on the pitch at the same time.
The problem is that it puts a lot of responsibility on the LWB and RWB. That's the thing that worries me even more than the back 3.
Our best performances last season against the likes of City and Chelsea all came with a back 3, so it's neither an alien concept nor an unworkable one.
A second choice lineup might be:
Greenwood--Ighalo
Fred---Matic---Lingard
James-------------------------------Laird
Mengi----Lindelof---AWB
Henderson
So there should be options off the bench (albeit lacking in the wingback positions again).
Again, I recognise it's not perfect. But I think there's enough from our recent history to suggest that a 3-5-2 is a formation that might get the best out of the players.