I'm not sure if he's the best defensively right now but he surely is close. The guy is nothing short of a rock out there and nobody is going to be able to outmuscle him. But for some reason I doubt Liverpool will let him go... if anything Benitez will relinquish Mascherano or Xabi Alonso in my opinion, but who knows what Rafa thinking. Whether it be Javier or Momo, we shouldn't be resting on our laurels when it comes to signing one of them.
Alonso's passing is too important and Mascherano is a jewel. he is not just a great player but a very smart player. I think Rafa realizes Sissoko makes alot of mistakes and Mascherano does the same job but makes less mistakes. Sissoko is more physical but to win the title you need less mistakes
He can pick between 2 of the best young defensive mids in the world. But either way sissoko is still a great player and with DD as his coach he can learn alot as a midfielder that rafa can't teach him.
I think considering the players we are linked with Sissoko would be a fantastic buy because while frings, almiron etc are good they are not the best in the world and sissoko could very well become the best in his position. and it is not like he is an inexperienced kid. he has been playing top level football for a while and doing it at a high level. he would walk into our team and galvanize it.
Could imagine the attacks we would have through del piero and nedved with all the balls Sissoko manages to steal and intercept in the midfield. they would have so many chances to just charge at the defense and into space once he passes it off to them
If DD can improve his passing and control he would be a devastating player for us.