I controversially think our best performances this season have came with Pogba in a 2. He ripped Leicester to shreds in a 2 man midfield, and Mata was fantastic in the #10 that day. And I still think our two joint best performances this season were home ties against Stoke and Burnley, I'd say we had 70 efforts at goal in those 2 games, absolutely tore them a new arsehole without the points to show for it, but yet again Pogba was in a 2 alongside Herrera, and extremely influential.
I personally think we look ridiculously fluent when we play 4-2-3-1 with Mata in the hole knitting things together, but I do agree the system has it's risks in the big games. I personally would play 4-2-3-1 against 13 teams in that league both home and way, and possibly at home against Everton. And go with a 3 man against the top 6 always.