@AC
"OTOH, since I know plenty who enjoy a glass of wine or beer without ever getting drunk, but no one who smokes weed without getting high, the percentage of users to abusers is lower with alcohol."
By this sentence, you seem to be implying that any intoxication from a substance = abuse of that substance. I do not believe this is a valid link to make, especially in this context.
"Getting high" with weed is nothing like getting falling-down-drunk. It's much more similar to becoming mildly tipsy. You wouldn't consider drinking to that level to be alcohol abuse, would you? To be impaired by weed to the same level as impairment due to drunkenness, you would have to smoke most of an ounce all to yourself - a ludicrous amount of pot to smoke all at once, and certainly nothing you could consume in a short amount of time.
Since you have said you abused both alcohol and pot, perhaps it's simply that you cannot imagine any use that is not abuse? I smoke weed regularly and I would certainly not consider my low levels of use to be "abuse." It is, rather, a relaxing way to wind down at the end of a week, certainly more relaxing and "cleaner-feeling" than the times I've chosen to wind down with alcohol instead.
I'd say, rather than banning things, let people consume whatever intoxicants they choose, and stop funding the expensive, failing War on Drugs.