Well, we definitely need midfield reinforcements in January, that is if we are serious about mounting a serious challenge for the CL. Asamoah and Lemina will be away for AFCON, and Sturaro and Hernanes won't be enough (and aren't good enough) for depth. Genoa's Rincon shouldn't be an option, because he really isn't an upgrade/improvement in any way. Witsel would be a welcome addition, but I don't really think he is that great either. We should have really tried harder for Matuidi in the summer (or pipped Napoli to Diawara; possibly signed Allan from them for 50-60 million as soon as we knew Pogba was leaving).
We should secure Kessie in January, and go all out for Verratti in the summer. Watch out for Udinese's Fofana. He could become an interesting player.