If your CB's are
awful in a 4 back system then they'll be exposed as well in a 3 back system no matter what happens.You're just delaying the time for them to
get exposed and deceiving yourself.Our problem was not about formation.It was about tactics yet no one saw this and thought 3 -4-3 was our saviour.Look at our starting CB's in 4 back: Koscielny and Mustafi who are all quality.The midfield is the problem.It's not the 3 back or 4 back.In 3 back also our players are not suited for that formation hence I
advice Wenger to switch back before it's too late.We need to revert to 4 back and play the right players in the centre.We needed a DM to make our midfield stable but we didn't so we have to make do with what we have.