I agree with what Hendandez was doing, but by the time he came off he was both tired, and marked out. They had the better of him in the second half, he was also losing possession more so in the second half.
It's all hypothetical but I think we would have excelled with Berbatov on in the first half. Hernandez was able to make runs through, and perhaps the better partnership for this match would have been Berbatov-Herndandez. Berbatov is our best forward in terms of keeping possession and the ball, and opening up space for others, he can hold onto the ball, pretty much anywhere. For me, that ability would have been better suited with Hernandez who might have had more to work off.
There was a deterioration in our play before he came off, and overall it had nothing to do with Berbatov. Yes, they marked him out easier then they did Hernandez, but how often did we even have the ball up there at that point? They had an easier time with Berbatov because our entire team performance had dipped, and there was far less service to him then before. I don't think it's fair to attribute either the lack of attack or Chelsea's progress down to the Berbatov substitution, at that point it was the team as a whole was playing differently, and tiring rapidly.
I know what you're saying, and I can see why we started him as well, without a few bad decisions we might not even be looking back on it and question it, but I feel the way we played that first half, and how Chelsea crumbled at times, Berbatov could have exploited that lax defence far more then either Rooney or Hernandez did.