We don't play 38 games in the league with a lone striker. We don't do it in the FA Cup, Carling Cup or even in all the CL games. So Berbatov is hardly a reserve.
This season and last season have shown that it is not all about just winning the games against the top teams or drawing against them. Being able to unlock the lower half teams is just as important. We can't do it playing the lone striker formation.
Everyone seems to prize the league as the most important but, then come across as it is our god given right to win the "gimmes" with whatever team/formation. Berbatov will be important for us next season. Him and Rooney will continue to improve playing along side one another and as Valencia/Nani become more of regular pairing, a better understanding will be formed with the front 4, we'll see us become more potent.
This season started off pretty weird with our constant changing of the midfield, Valencia bedding in, Nani/Giggs in and out of the team and Berbatov/Rooney still building a partnership. Then the injuries to both Rooney and Berbatov, then more problems with midfield playing in defense and then we've gone with a lot of games playing with a lone striker. There was the whole question mark of Rooney playing deeper and Berbatov being further up the pitch but, I think that has finally been settled now.
That hasn't helped the Rooney/Berbatov partnership but, they've still shown marked signs of improvement playing along side one another. Selling him is not going to the way to go IMO because I think if we try buy a big name striker, he'll just get moody when Rooney is playing the "big" games on his own.