I hate to say this, KevinW...but your letter is very likely to get absolutely no response. I don't want to be a jerk here, and I am not disputing that you did not have a good cruise, but seriuously, a letter so opinionated and negative is quite unlikely to be taken seriously.
Please don't take these comments the wrong way. If you had a bad time, you should write a letter, and my hope is that you'll write a letter that will be read, and acted upon.
Let's take a minute to address what you've written.
1-Alcohol. EVERY cruise line has a similar alcohol policy(I believe the exception is Seabourne...which is all inclusive anyway) so your argument here is completely invalid, as you violated the rules of the cruise line. Bringing Alcohol onboard is expressly prohibited. They return it on the last night, per their policy, the same way they return all alcohol purchased on shore on the last night. This allows you time to pack it in your carry-on for the trip through customs. It also avoids the congestion of those 100 rulebreakers clogging up customer service during disembarkation.
2-tv too small? Did you pay thousands of dollars to go to hawaii to watch TV? Your letter is not going to cause the cruise line to buy 2000 new tv's
3-Handicap issues... I feel bad that your father had some issues, but you have to understand...you're on a SHIP. and the tender issue...you are trying to drive a scooter from one moving ocean going vessel to another. Now if he was discriminated against, or was unable to do the things that able bodied individuals were, such as boarding the tender, going ashore, or getting into his stateroom....then you have a valid complaint. I see what you wrote as testomony to the ship's crew doing everything they could to get him onto the tender. He can't walk...that's nothing to be embarassed about, and I applaud the crew in this instance for finding another way to serve him when a mechanical failure made their job much more difficult.
4-No Champagne Waterfall? I certainly don't book my cruises based upon the availability of a champagne waterfall. I don't think I've ever even seen one.
5-The Band playing at the poolside were well below average....that is an opinion based statement, and not likely to get anything accomplished
6- You didn't like the shows...I don't believe this letter-worthy complaint. I've not liked the shows on many cruises...I just didn't go to them.
7-Robes in the stateroom. In my experience, stateroom robes are only issued for free in suites, and sometimes as perks for multiple cruise club members. Make sure you are aware of the cruise line's policy regarding this before you complain about it. Were you promised robes in your stateroom?
8-Cabin steward in your way....did you place the do not disturb card on your door when you left? if you do not do this, the cabin steward will see you leaving, and assume it is time to clean your room. Also, if you were noticibly annoyed that he came to your cabin too early...do you think perhaps he serviced your cabin later in the day as a direct result of that? In one paragraph you complain about him being too early AND too late in cleaning your room.
This is not a flame, but more of a suggestion on how to make your letter more useful to the cruise line. If your intent is to effect change, your letter should be short, to the point, and only address issues that can (a) be changed and (b) be seen as true issues, and not opinion based.
Complaining about lack of activities or ammenities will get you no where. Mentioning the cleanliness of the rooms, cold meals, the difficulties concerning your father's mobility, poor dining room service, and overcharging (be it for inroom movies or anything else)...those are valid complaints, and need to be addressed.
I hope you haven't yet sent that letter in, so that you might re-word and shorten it so that it has more impact.