I wouldn't worry about anyone finding it tacky. It is a Disney cruise and meant to be fun and magical. If someone wants a super high end experience without the fun touches like decorated doors they can fail Cunard. The true Disney spirit that Walt wanted was for everyone to be able to feel like a kid. Decorated doors add to that fun. At the end of the day, you probably won't ever see any of those people again, so eek really cares what they think? Go. Have fun. I hope your daughter had a great birthday!