Zabaleta is the more solid fullback out of the three of them.
The thing with Clichy is that most just focus on his defensive lapses but his contribution offensively is not anything either. He will make the offensive runs all day long down the flank but his distribution, end product and composure when he gets into dangerous offensive positions has been weak.
As far as RB is concerned, you've bought Boateng, wasted him and you're planning to let him go, so you need another one. In regards to Yaya, he is a world-class, but his partners are not. That's what I specifically meant. Especially Gareth Barry could've been replaced with someone classier.
Boateng was signed to play anywhere across the back, got injured, and now wants to leave. We haven't wasted him, he quite simply hasn't been available enough to be an important part of the side. We have Richards and Zabaleta for right back. Now we've signed Savic to cover CB and RB.
He's great, but I had more creative (it isn't his forte) players in mind...Not typical #10 like Silva, but someone like Lucho Gonzalez for a CM (not saying that you need him, but this is the type of a player I have in mind).