Given that he's bought Migs, Clyne, Sakho, Lovren, and Moreno (plus Toure, Bogdan, Gomez and Manquillo on loan), that's what, 70-80 million spent? So it's hardly been neglected. If it was money well spent is a different issue.
Attackers: Balotelli, Studge, Aspas, Lambert, Borini, Ings, Origi - that's around 60-70 million. Obviously gets more if you add Benteke, Firmino and Markovic (last two I would count more as midfielders, Benteke not yet signed?).
Midfield - Lallana, Markovic, Allen, Firmino, Coutinho, Alberto - that's about 100 million.
I've missed quite a few off, but I think that's the main (most expensive) ones.
We've certainly made more money selling attackers than selling defenders.
EDIT: Forgot Can - so that's around 10 million more for either midfield or defence.