There are better players than him nodoubt, but instead of paying the majority of your transfer $$ on a replacement for him (whoever we will sign gonna cost no less than 25 mil whether it's Jovetic, Lavezzi....).
We can get him back for faaar less than that, and he will be pretty useful for us (anyone disagree with that must be a biased). He had so far scored 9 goals and 5 assists this season, he's not a Maradona or a Del piero but the man can definitely add a spark for our team.
From a financial point of view, if we sign him back we'll have an option to spend the majority of transfer money on other positions (defense and mid) instead.