I think there is a cream or fat element to buffalo sauce that hot sauce lacks. If you shake a bottle of hot sauce, it has the consistency of water but good buffalo sauce will have a more custardy consistency. Buffalo sauce has heat and flavor, whereas hot sauce is really just about heat.
I remember looking at the label of some Hooters wing sauce in a grocery store (a typical 'good' buffalo sauce IMO) and a table spoon had an incredible amount of fat in it. Enough to make me put down the jar and not buy it, even though I wanted to. Didn't think to look at the ingredients.
The only good substitute I've found here so far is called 'reggae reggae' (flavor) sauce, nice flavor (jerkish) and substantial heat. A little too sweet, but alright.
ETA: ...based on the opinion/experience of a person raised on BW3 wing sauce...