Masters of Doom does seems to want to, however accurately or not, set Carmack up as the antagonist of its story against Romero as the hero sometimes. I think that readers just largely didn't notice that since Carmack's heroic image was already so firmly established. In fact some of the early-ID stuff really does seem to raise some questions. (Was Tim Willits mostly Carmack's protégé, for instance?)

yeah and Doom Guy takes a lot of issues with Masters of Doom. You get the impression that MoD was looking to create a McCartney vs Lennon story and stretched the truth to do so (there are several factual errors in the book).

In Doom Guy, though, Romero says that after he left iD, he heard from others still working there that the company had become something of a dictatorship under Carmack, and that within X months (I forget how many), half the company had quit. Romero also qualifies several times that they were all in their early/mid-20s and didn't have the requisite life experience to be handling business situations well