I think all of your points are valid, including the stiffing remark. I'm sure some people knocked themselves out for jerks who left the envelopes empty at the end of the trip.
Although is sounds a little rude, I may discuss tipping with people in advance next time I cruise. My waiter was outstanding, although obviously overworked, which made his time talking to us even more special. My room steward, though, for a Penthouse Suite, was not great. Average. He said he performs silent service, the popular thing now, but he was outspoken two times when he returned my page to tell me that on on-duty hours he was 1. at dinner and 2. at a staff party.
They work very hard for very little money, so I would never remove an auto-tip unless one punched me. Seriously. I feel for them. But if you want special service, maybe a few bucks in the pocket the first night would help.
With how little they're paid, I think $9.50 or whatever a day for them to share is a pittance. I spent multiples of that on drinks each day.
So, perhaps tossing a few more over in advance might get you the service you desire.