Bravo's the better tackler and provides better cover, but Iraola serves as a second deep playmaker. It keeps teams from man-marking Pirlo out of the game while still providing a capable defensive presence. He really helped us to play out of the back this past week.
I don't know that he's a long-term solution there, but he's very capable at that spot.
Not trying to be rude here, but you keep telling me "it's not that hard to make it work" without really giving a system that works without massive turnover of the roster and a serious mentality change.
(See how far everyone has to move up the pitch to make a difference in the attack here? You're asking Pirlo to run a lot (which he can't do), Lampard to track back consistently (which will be a struggle), and Allen and Matarrita will have to have superhuman stamina. I rate both of them highly, but you're asking a lot.)
You're already talking about major personnel changes to make it actually work, and that's not something that I addressed in my post. Even then, I don't love that idea, and I don't see Vieira playing with a target man in a direct system any time soon. (Although I do agree that the pitch requires a system of that sort.)
Mata is great going forward, but is not solid enough with his positioning to be dependable holding down the entire left side. And a right side with Pirlo providing defensive cover for a wingback/wide defensive winger neutralizes him in our attack as an advanced playmaker, which is the only area he's been remotely helpful for us at this club. Direct teams will destroy us on the wings (no one to cover their positions when they're caught upfield). They'd play physical against the midfield to wear it down early.
Lampard is still just a slow box-to-box guy, and doesn't have the pace or the stamina to play that sort of a role all year.