My understanding is that MP had very little input into signings in the final two years of his tenure.
Negredo, Fernando, and Navas were, I believe, signed on his recommendation. Players like De Bruyne, Sterling, Mangala and indeed Bony, were very much Bergiristain signings, in preparation for Pep's arrival.
Players are scouted and researched in detail by the DoF team prior to signing. Some work out, some don't. That's football.
Don't blame MP for poor signings, and bear in mind that 5 years before he arrived, we didn't even dare dream of reaching a CL semi final.
He was a very good City manager.