If he can make it back to the battlefield, Sakura should be able to heal him via Katsuya. I don't think he used too much chakra against Obito, and the wound looked like it was more to his shoulder than to a vital area.
Plus, I think Kishi would want his death to have more of an impact. Right now, the previous Hokage are back, the current Kage and Orochimaru are on their way to the battlefield, and Madara is about to sacrifice Obito (or something) in order to become the Jubi's jinchuriki. There's just too much going on for Kakashi's death to make an impact (especially if he is stuck in the other dimension). Plus, I would expect Team 7 to be affected by his death, but it just doesn't seem right for him to die right now. We will see though.