Executive producers/creators Max Mutchnick & David Kohan said the original fucking awful finale was set because they assumed at the time that was the end of Will and Grace.
Now, they look back and realize they don't want the upcoming revival season to be focused on the pair being parents (good or bad), but just about Will and Grace. So the show sees the pair as single, childless, and still living together in Will's big ole apartment.
Jack and Karen are also back to how they were pre-finale. Jack's living in the apartment across from Will & Grace, and Karen's got her fancy rich lifestyle. Unfortunately Harry Connick Jr.'s fucking awful Leo will be back in some form this season.