Regarding the shower on the boat; as far as boat showers go, this one is above average in size. Our guests have been choosing the marina showers, given the close proximity. Also, with a 5 gallon hot water heater, shower time would be limited. In Florida the water comes out of the ground at 70°F, and once heated, stays warm in the heater for quite some time. So unless you used all 5 gallons of hot water you should never have had 'cold' water to wash your hands.
I don't think requesting to shut breakers off when not in use is unreasonable, as it is standard practice for most boaters. We do have a new water pump, and will continue ask guests to shut the breaker off when leaving for the day.
The WIFI was working the morning you arrived, and the afternoon you left, so not sure what was happening for you. No one has had problems with it since. The same with the air conditioner. The boat has been occupied since your departure, and the weather has been warmer. (I also had it working, several times, while cleaning the boat.) A quick message may have helped resolve these two issues you were experiencing.
My response is only to clarify that all systems on the boat in good working order, should future guests use your experience as the standard.
I completely understand your frustration with the electrical issues, which are now resolved. I apologize for not being able to have it repaired during your stay. Running out of fresh water has never been a problem, given the water tanks hold 150 gallons. I have had guests stay up to 10 nights, with no water issues. A call, or text, would have quickly solved the issue.