I agree with @Nek Sanalet , we don't have the FBs necessary at World Class level for a 4-man backline. And that's OK, because we DO have the CBs necessary for a very effective and tight 3-man backline. I'd like to roll with this and see if it gains any traction: Donnarumma, Perin, Meret Chiellini, Bonucci, Romagnoli, Caldara, Rugani Verratti, Jorginho, Baselli, Tonali, Barella Florenzi, Bernardeschi, Chiesa, Insigne, Conti Belotti, Immobile, Zaza, Pellegri, El Shaaraway Some stretch picks in there - Tonali and Pellegri - but sometimes you gotta gamble on the younger talent when club managers have no balls to play them.
It's also worth noting that both Cristante and Pellegrini are starting to play better lately...especially the latter. Hopefully, its not a temporary spike in form.