We typically do buy the package but the new increase won't be an issue for us at this time as we're always on longer cruises. Having said that, these increases likely presage that happening fleet-wide in the not too distant future.
We've never approached the 15 drink limit - I've done, perhaps as many as 8. But one of my favorite pours is the Cadillac Margarita - simply a pour of Grand Marnier over a spoon into an otherwise normal margarita. It counts as 2 drinks, something I'm not too crazy about as I have to wait 15 minutes to get the Grand Marnier after ordering the margarita. In essence,my 8 drinks would count as 16 - not good. Still, if you have 5 or 6 drinks a day, you'll save some $$$ with the package!
BTW - coffee, sodas, and, I would guess water, do not count against the 15 drink limit. Unless something has changed, the limit only applies to alcoholic beverages.