I've done mileage buys like this a few times in the past when the bonus has been 100%. But yes, they did a MAJOR price hike on miles: to get 60k + 60k bonus used to run $1600, and now it's $2100? Eeek. Sorry Delta, not doing it anymore... especially since there's such little availability in Biz Class on int'l flights, and if there IS availability, even in the off-season, it's always 150k-200k miles from LAX to anywhere in the EU.
Kirby