As has been said many times by many people, the problem was not in selling Riise, because, despite his obvious talents, we needed someone better.
The problem was in trying to replace him with a mixture of Aurelio, Dosenna & Insua.
Aurelio was arguably a better player - certainly more cultured - but too injury prone.
Dosenna was a horrendous decision and Insua is not good enough to take on the responsibility of first team regular.
Given that on Insua remains now, and Benitez has admitted that he played too much, it seems absolutely6 certain that we'll sign a new left back.