I think you summarize it pretty well. Plus the business with the drum machine. How the F are you gonna rock without a human drummer? Might as well go home.
With Shellac, I bought one record and thought: cool, cardboard cover, cool, extra thick vinyl, cool, nice job recording that guitar and those drums. Then I listened to it I think twice.
Talking Heads, though, I do love them. Appreciate them more as I get older, in inverse rock band appreciation manner.
As I see it, the problem with Big Black is twofold. First, everything from the music to the lyrics sounds contrived. Secondly, if it's abrasiveness and unpleasant aesthetics they're going for, they fail miserably on both counts. I've heard old free jazz records from the 1960's that are far more abrasive and unpleasant sounding than anything Big Black ever recorded. Some people say they like Big Black because they offer a unique insight into the ethos of Middle America. For me, it seems like Steve Albini is just trying to piss people off. I'm just not impressed by them.
Aside from a handful of good songs, they mostly suck.
Oh and now playing: