The only gaping hole really is CM and we may fill that before the window closes.
CB could do with an extra body but if we play two at the back Evans, Jones, Rojo, Smalling and Blackett isn't world class but not a glaring hole either.
Would you say your current back line is world class or also in need of additional quality?
I'd say our CB depth is substantially better : Smalling is not rated by many Utd fans and I'd agree with that, he's a utility player, as is Rojo. Blackett (and Keane) is no better than Liverpool's Wisdom - and look where he is. Evans is good and a better CB than Jones who is good enough to be your CB #3 or 4 and is better at RB.
Lovren, Sakho, Skrtel and either Agger or Toure is a far better 4 and I expect to see a couple of solid partnerships there before the season is out.