First off lets deal with Jackie's food crazed pity party. WHO CARES. This is just old business rehashed. Remember Donna trying to get the beef jerky from Jackie after one of her break ups with Michael.
Next, bringing back Carolyn was just weird. If you want to bring someone back, bring back Rhonda. Fez was not scared to death of her, and they had some touching history! Makes much more sense then Carolyn who was just plain nuts!
It appears that the writers are really just filling time at this point in the series. I can only hope that the finale goes better and brings back some of the life and fun this series used to have.