My take on the tactical mistakes:
1. Toure should never have starter. KDB in the middle, Sterling and Navas on the wings (or in my opinion Iheanacho and Navas, given how poor Sterling has been). Toure in general is mishandled this season - he should be brought on as a 60-70 minute sub to impact the game.
2. Fernando plain and simple is not good enough. If fit, play Delph who at leasts adds some creativity.
3. With 20-30 minutes to go, Wilfried Bony is a must. Despite him not performing his power and hold up play would be pivotal to make spaces up front. The last 20 minutes should have been Bony + Aguero or Bony + Iheanacho.