On the question of speed.
I tell students that they should control their speed with the transmission (forward, neutral, reverse) to maintain steerage way. The throttle should only be used in reverse to stop the boat.
We usually use fin keel boats. Full keel boats need some additional speed to maintain steerage way.
As I've indicated, I agree with using the transmission. The issue is how much some skippers are depending
on the reverse thrust to stop them. If you are moving at a speed at which the lack of reverse thrust will allow the boat to "bump" the dock, thats one thing. However, if it causes a 10 ton boat to climb the dock and ram into a boardwalk in back of (and 7 feet above!) the dock....thats another issue!
Regarding steerage; As long as a full keel boat is headed straight for her slip, wouldn't she be pretty much locked in (a strong cross current not withstanding)? I thought tracking is one of the advantages to a full keel. If not (and the boat actually needs the speed), I would certainly have nimble crew ready to perform the spring line trick on every approach. If a kid on the boardwalk had been watching us dock, it could have been ugly! Not to mention... it's no way to treat a lovely 60 year old boat.