I think it depends on Yaya. As I see it his problem is not defending, he was a great defensive midfielder, and a very good CB at times for Barca too - his problem is going forwards, and then getting back in time. Last year, when our attacks became pedestrian we all looked to Yaya to provide the spark, and when he got forward, he was not able to get back in time.
I see the club making attacking purchases as a sign that Yaya will be much more conservative in attack. We're taking the burden of attack away from him, and that means he'll be staying in position beside Fernandinho, ready to do his defensive work when called upon. With a front 4 of De Bruyne, Silva, Sterling and Aguero, we don't need his extra contributions in the attacking third anyway. He can sit back, control the tempo of the game in what I suppose people would call the "pirlo" role these days.
I also think he'll play a lot less. He's too old to be playing the sheer amount of minutes he has done recently. He's 32, lets treat him like it. Some people on here are acting like he's undroppable and will play 90 minutes for 60 games this season.