Lee is awsome but it is a fact that his strength can only go so far. Sasuke, Naruto, and Neji have all surpassed Lee. Even if Lee was healthy he could get his ass handed to him by someone must weaker. What if he fought one of those rain nins that Naruto, Sasuke, and Sakura fought in the forest. He would be stuck in their genjutsu with no way to escape. Just face no matter how cool Lee is at this moment he is nothing. Even if he was healthy he would probably only reach chunnin level, whereas Naruto, Sasuke, Neji, and even Shika would be able to become jounins.

BTW sorry about my Naruto>Itachi rant in the other thread. It was a pretty weak argument.