For a contrary viewpoint - as a non-champagne/sparkling wine drinker, I find it pretty darn frustrating that the pre-departure drink service is actually better in domestic first than on international BE. Domestic first, you can order most of the beverages available off the cart while on the ground; international BE, you're stuck with orange juice or champagne. Even requests for non-alcoholic soft drinks have been denied for me multiple times...ugh!

When Delta reworks the BE service standards, I'd nominate flexibility for pre-departure drinks as a place to start - for a habitual domestic first flyer, being told "no" as your first interaction aboard a BE flight is not a good start to your impressions of the service.