To be fair, alcoholism is not a character flaw, but a disease.
It's an addiction, but I've never bought the propaganda that states that it's a disease. That gets the drunk off the hook way too easily, to my mind. Too many voluntary actions are required by the alcoholic (buying the drink, drinking the drink) for me to accept it as a disease.
"Voluntary" actions can be performed in a state of compromised judgment or under the influence of a physical compulsion -- for instance, the way the action of suicide can be brought on by the mental illness of clinical depression. Addiction is recognized as a mental disorder by the medical community, just as depression is. It's not "propaganda," it's the accepted scientific understanding of the condition.
One thing that's pretty clear about Roddenberry is that he was addicted to just about everything -- alcohol, drugs, sex, fame, control, you name it. And he ruined a lot of things for himself and others in the process. That doesn't seem "voluntary" to me. It suggests a pretty deep-rooted neurological condition that he couldn't entirely control.
And given that Majel Barrett stood by him despite everything, I think she probably saw it the same way. I think it would be arrogant for any of us to think we knew better.
Can I ask this though? Do you think Roddenberry's demons inform the creation Trek? Or, how about - how much of Roddenberry is in Trek? It is said he didn't live the ideals the show espoused - but is that always necessary?
Maybe those of us who are most screwed up have the greatest need to believe in a better world. And just because we don't always live up to our ideals doesn't mean we don't wish we could. I think Roddenberry believed a lot of things in principle that his appetites made it hard for him to live up to in practice -- like respect for women, for one thing.
Anyway, there's a grand tradition of great creators being screwed-up personalities, neurotics, depressives, addicts, libertines, etc. The most abnormal minds are often the most creative ones. So there's no shortage of people who have created visions of great beauty and wonder and shown us the heights of human potential, but who have been tragic or disturbed or just unpleasant in their own lives.