I think Zabaleta is perfect for midfield enforcer role. If we compare him to De Jong, he is faster, and has more skill going forward, and doesn't lack anything in tackling department. Look at Mascerano, I honestly think Zab is a better player and combines well with Silva, Tevez, Aguero.
I would even go as far as to consider him for captain. Kompany has faltered slightly this season and maybe removing captaincy could help him refocus. Zab has very good english and spanish, so can communicate with all players and comes across well on camera.
We are already well covered on right side (especially when Richards returns) and I think it is worth giving Zab a try in the middle.