I like the idea of three at the back, I think the problem then becomes having four "wingbacks" who can spread the load of the toughest role in the modern game.
No surprise City already have five and are looking to upgrade a couple, Liverpool have the best pair in the EPL with backups, Spurs are buying two more to swap with two of their current crop, Chelsea are on the hunt ... it's not rocket science.
Everyone in the top four is looking for upgrades at wingback and they already have far better squad depth than us.
Playing a back five requires a squad that right now we simply don't have. Square pegs Round holes how many times will we rinse and repeat?