Recently took a short cruise on the Holiday before it moved to the Caribbean. There were many good things happening on this ship including excellent food in the dining room. (But the waiters are still dancing to "Hot Hot Hot", the same as 10 years ago.) Though it was a good value for the money there are plenty of things Carnival needs to do on these older ships.
The bedding was old and ratty and needed to be replaced. The rooms are looking very worn and dented. We had problems with the drainage in the sink and shower and it took a day and a half to get it fixed. It was disgusting. Maybe there's nothing they can do to the installed plumbing lines but maybe the whole system can be flushed and drained more regularly.
This ship sailed out of Los Angeles, the entertainment capitol of the world. Unfortunately, it seemed they did not cast talent from LA. There must be 2500 out-of-work professional singers in LA. None were on the Holiday. The shows would have been much better with more talented singers and dancers.