Read: "I want to work in projects where I can implement muh stuff".
Really? How much of his stuff has went into his side projects, in the end?
Read: "I don't like to work with this people anymore. They are using my name to do idiotic side projects, but I can't take the lead in anything here".
wat
Obsidian hardly used MCA's name for "idiotic side projects". That would be MCA himself.
Don't get me wrong, I also would want more of MCA in Obsidian's games. But my guess is that his involvement in their projects was mostly limited on his side. If not, then it's probably due to Feargus (and perhaps other people in upper management) preferring Sawyer's project management style over MCA's. The Sawyer/MCA clash of personalities is probably mostly, but maybe not entirely, made up by the Codex projecting their own opinions on recent events.
More likely, MCA's departure has to do with him doing too much on the side - which of course in turn may be due to him feeling constrained at Obsidian, which indirectly is a consequence of upper management handing more responsibility to people like Sawyer.
He announced his departure on social media and caught everyone by surprise. It's obvious that some conflicts happened there.
It depends on what you mean by "conflicts". Obviously, there was a conflict of interest. The question is really if differences had to do with design approaches, or more practical issues (keeping to schedules, being available for work...), or even personal issues (in which case we might never know what really went down).
Codex seems to believe that differences were due to MCA and Sawyer having different design ideas. I don't think that was the root cause.
It would be rewarding if the rest of the game were developed like that, but it isn't.
I haven't finished the game yet, so...