While I agree he obviously played a huge part and had a very good season individually, I still definitely see Mahrez replacing him. Yeah Sterling scored loads of goals, but I do think it was very system dependent. Just like how Pedro scored 23 and 22 goals 2 seasons in a row for Pep, finishing as their 2nd top scorer in 09/10 (ahead of Ibrahimovic and Henry) and just 1 behind David Villa as the 3rd top scorer in 10/11. Pedro was the weakest part of both of those sides obviously, but he just suited the role he had to play where his off the ball movement played a big part to finish off a lot of chances. Sterling I see kind of the same. His role is of course important, but it's based very much on the rest of the system with his pace to put him in goalscoring positions. Mahrez is a much better player individually and in terms of build up play and creativity, while Sterling's goals for them could probably be replaced relatively easily with others providing the finishing touches (Mahrez scores his fair share too).
Basically, I'd say that each midfielder is absolutely vital for Pep's City (fernandinho, david silva and especially de bruyne), while Aguero is obviously the main goalscorer and then Sane more important for Pep and City because of his pace and the width he offers and how he creates so many chances. Sterling is the most expendable out of that midfield and attack (though they'll all just be rotated for the most part I'm sure). Come the more important games, I'd guess Mahrez and Sane get the nod ahead of sterling though.
