There is a difference. Esposito was more of a late bloomer.. Russotto has been rated since he was like 15. I am sure Napoli wouldnt mind Russotto scoring 17 goals like Esposito did for Cagliari one season.
Russotto can be a fantastic player if he gets the right coaching. Well just have to see if Reja is the guy. With guys like Lavezzi, Hamsik, Santacroce and Maggio, he can flourish. It's a good environment for any young player