I'm going to be a little controversial, because when it comes to drink-driving, you're not even allowed to suggest that it's okay to have half a shandy with your pub lunch and then drive home these days.
As far as the penalties are concerned, I'd be all for harsher ones as long as mitigating circumstances, and (to my mind, more importantly) intent could be taken into account, resulting in lighter sentences being given out (maybe a 6 week ban and a smaller fine) in some instances where the offender is only just over the legal limit or where the public were not put at risk.
A friend's brother who was prosecuted for "drunk while in charge of a vehicle" for simply visiting his vehicle in a car park to place a new pay & display ticket in the window. He already had the ticket in his hand (why would he have bought one if he was planning to drive away?) but still ended up with a full-strength driving ban. This is something that could happen to anyone who'd intended to drive home but changed their minds and had a few more with the intention of getting a taxi home instead. I suppose the safer option is to leave your car alone and take your chances with the parking fine.
A friend of a friend this time, who ended up involved in a domestic with his wife. She was damaging his car, so on the spur of the moment he decided to move it to limit the damage. The police attended the domestic and he ended up with a drink-driving ban because he'd had a few drinks before doing it.
Then of course there's people who are banned the morning after, who did not intend to drive while over the limit. Maybe there's scope for treating someone who's just over the limit in the morning more leniently than someone who's just over the limit late at night.
But none of this will happen because we have a government that's promoting a war on drink. It's also in favour of anything that improves safety, no matter how marginally, as long as it doesn't cost them a bean in enforcement (and is preferably able to turn a tidy profit.)
Let the flames commence