I can't answer about the drydock schedule, but we were on Constellation for a 10 night cruise that sailed on 3/27.
The ship was in great shape as far as we could see. Nothing at all jumped out at us as needing attention. The only major area we can't comment on is the main dining room, as we never ate t here once during the entire voyage.
If you do go, and an entertainer named Perry Grant is still on board, be sure to catch his act in Michael's Club.