On a few cruises since the restart the steward told me when he would be available to clean the room. We weren't really given a choice. I'm sure if I pressed I could have gotten him to relent but it wasn't a big deal to me, it really doesn't matter when they clean the room.
You can adjust gratuities as you see fit - either by adjusting the rate at guest services, or by removing the automatic gratuities altogether and tipping in cash, but Carnival has continued to cut service and increase their suggested daily gratuity rate.