On the surface this might look unnecessary. We currently have the first choice defensive midfielders for the English and Dutch national sides, plus the once-great Patrick Vieira and Vincent Kompany and Pablo Zabaleta as able auxiliaries. But we were left fairly exposed at times last season, with de Jong and Barry probably asked to play too much football notwithstanding the fact that their partnership was fairly static and one-paced.
Yaya Touré isn't David Silva but he's not Nigel de Jong either - the attacking side of his game is better than he is given credit for. He's able at carrying the ball forward, he gets into the box at the right moments and he shoots well. So this gives us good options. We can pair Yaya with Gareth Barry (for easier games) or with Nigel de Jong (for difficult games). When we want to put three in central midfield we can either go with Yaya at the peak of the triangle and Barry-de Jong behind him or with Yaya in the base and David Silva ahead. We're generously stocked. But we should be playing a lot of football next season. If we get to the final of the FA Cup, League Cup and Europa League then we will play 69 matches. Obviously that won't happen but we will probably have a 50-60 match season. Given the World Cup involvement of Silva, Barry, de Jong and Yaya there are inevitably going to be fitness issues and so we will need the extra bodies.
He comes with some top level experience, having been part of Pep Guardiola's all-conquering Barcelona team. As it happened, he was not an automatic first choice, which is why he left - but he still managed to start 37 games last season and 43 the season before. Guardiola's personal preference for Sergio Busquets and Seydou Keita meant that Touré did not feel sufficiently wanted but he was always the next man in line when either of them missed out. He also filled in at centre back when required, including during the 2009 Champions League final. Two of the starting eleven from that evening have now come to City, which somehow feels right.
And let's not forget the fraternal factor here. This is the third pair of brothers to play for City since I've been a fan, after the Brightwells and the Whitleys. While this is fairly interesting it does represent my main concern with the deal. I'm not a Kolo Touré fan and would be quite open to our dropping him, making someone else captain or even selling him. Now his brother is on the team this would become more problematic for Mancini. One interesting prospect this season is whether a Francophone/West African/Arsenal clique develops (around the Tourés, Adebayor and Patrick Vieira) and whether this is similar to the Brazilian clique that developed under Hughes. Vieira's relationship with Mancini will be crucial. I'd make Vincent Kompany captain (there's a post on this coming some time soon), who is in fact on very good terms with the aforementioned players.
Anyway, Yaya Touré is a quality player who played in arguably the greatest club side of the last decade. A well-judged addition to an ever-strengthening squad.