When did you last see any of our central midfielders getting into the box for a tap in from open play? We don't get central midfielders into the box enough, we don't have the energy to do it unless Fernandinho is deployed further forward. Accommodating Yaya means Dinho has to sit and hold the majority of the time.
No it doesn't. Fernando isn't that type of midfielder. He's a lot of things but he isn't a goal scorer. He's only had one season where he has scored more than 5 league goals in his entire career. Fernandinho would only theoretically have to sit if we were playing Dinho and Toure in a 2 man midfield, where in that case the player who is defensively better would sit and the player who is better offensively would push. That's a fairly simple concept.
With Fernando in the team, there's not really a reason why Fernandinho can't push forwards. He did it in tandem with Yaya against Sevilla away to great effect.
There's several other reasons for why midfielders don't score tap ins without even bringing Yaya up.
1: We don't cross (Clichy/Sagna), or when we do, the cross doesn't beat them first man (Navas) or it is actually a shot (Kolarov)
2: Navas on the right occupies the exact same space as Sagna/Zabaleta. It's totally ineffective and has been for the last 2 years. It doesn't allow for more crosses, all it does is take away an attacking option. It actually stops the isolation that Navas probably needs to show off his only attribute (speed) so instead of getting a chance to cross we play the ball back across the outside of the area, over to the left, and back to the right. Aguero is hardly ever even in the box.
3: We have zero wide threat. Sterling needs to cut back and Clichy just isn't effective as an attacker. Kolarov can cross at times but he's god awful at almost everything else.
4: Nobody shoots from outside the area, or when we do, we don't hit the target enough meaning there's no chance of a rebound/tap in.
5: Teams totally crowd their own penalty area against us. Often there will be 9 or 10 players in or around it. Unless we push forward with the same amount of bodies, we have a less than favourable chance of finding enough space in the box to score a 'tap in'.
I'll finish by saying Yaya didn't play on Saturday and we played against one of the worst defences you will see in top flight football, yet we didn't create a single chance against them, nor did we get bodies into their box.