There is a tendency in modern football to play 1 striker and 2 very attacking midfielders who play a role somewhere in between an old school winger and a 2nd striker. It’s a front 3 in attack and a 5 man midfield in defence. Both Barca and Real Madrid play that system. When the main striker is out they just shuffle the pack so a replacement player comes in somewhere in the front 3, each player being capable of each role.
Looking at our squad we have Aguero so the main striker is sorted we then have various players that can make up the 3 however they all have their drawbacks namely:
Bony – not mobile enough to play wide, needs a significant upturn in form to play central.
Kelechi – could play anywhere in a front 3, needs to work on his right foot.
KDB – great player but prefers a central role. Not a striker.
Silva – as per KDB, prefers to drift centrally and get on the ball.
Sterling – needs to hit form / score more goals, could be ideal for a wide spot.
Navas – good pace / discipline and a natural right winger – final ball is poor, not a striker.
Nasri – prefers to drift around, not a striker and poor discipline for a midfielder.
So in short any 2 you pick alongside Aguero brings some sort of compromise when you compare them to the best in the game i.e. the likes of Bale or Neymar. So it would not surprise me to see 1 or 2 of these players leave and a more adaptable striker / wide attacker brought in.