What an idea...punish an actual harmful ACT instead of an activity which MIGHT lead to it! Oh, and establish an absolute, all-inclusive age-of-majority, and EXPECT them to act like adults at that age!
I think you've got something, there. My only change would be to raise the BAC to .12. The lower numbers exist only to facilitate the arrest of those who have had 2 drinks, hardly enough to sauce a normal-sized person. Gets revenue for the police and the insurance companies, though.
I'd go for that. ...And I'd imagine there isn't much of a difference in impairment between the two figures.
We're on the same page; it's all about personal responsibility. You said it best -- "punish the crime, not the activity that might lead to the crime." Drinking heavily in one's home might lead one - a weak brain-dead - to beat one's wife, or to drive drunk, but should drinking be outlawed because of that? Of course not, and that failed policy has already been tried. It's now time to apply the same standard to other drugs.