I've been on 9 Princess cruises and can guarantee you that someone does care and does do something about problems on board. Any ship is like a hotel and things do break. Most complaints you read/hear are from those who are seeking a free cruise by whining. They feel that they "deserve" compensation and what was done is never adequate for them.
The Grand is the first in the Grand Class of Princess ships. She gets refurbished at regular intervals, but they paint, change out carpets, mattresses, chairs, and many other things daily.
I am sure you have nothing to worry about. If you experience a problem, call down to guest services immediately. A smile, kind word and a pleasant request will go miles at having your problem resolved quickly.
We've had a few things break down on our cruises, it's never taken them more than 4 hours to fix anything. They couldn't have been more efficient and more pleasant and apologetic.
We just got off the Epic. She's a brand new ship and 2 of the 4 elevators in one bank were out of order. It happens. As soon as they got the parts, they replaced them and the elevators went back into service.
Please don't worry. You'll have a marvelous time.