While I find responsible imbibing to be ok (Jesus DID drink wine), I agree that letting it get out of control skirts the issue to if a member of clergy can carry out their function as a faith leader, if their minds are clouded by alcohol.
I believe we have far greater problems in the church these days than what people consume.
There was a guy who used to sidewalk preach in NC that used the money he raised to buy his liquor. His theology was more sound that what I hear today from guys who can fill an arena.