Aguero's always played his best football with a strike partner, be it Tevez, Dzeko or particularly, Negredo. This season, he's found himself up front on his own and isolated in a large majority of our games. He still doesn't look 100% to me in terms of his burst of speed but maybe that's just the multiple injuries finally catching up with him like they did with Torres.
There's only really been one game this season where I've watched Aguero and thought he looked his most dangerous and effective and that was the FA Cup win at Norwich where he played up front with Kelechi. Now why this hasn't been done more often is baffling to me. I'm aware Bony needs minutes and has cost a lot of money but him and Kun just don't look on the same wavelength and don't seem to have any chemistry whereas Kelechi has bags of energy, pace, skill which would compliment Aguero perfectly when he's not 100% fully flying.