What you are suggesting seems a few steps away from an aim bot to me because (what I get out of this) is that you want there to be, either, an indication for your guns current fireing range and the range of the ship you are fireing at (as if the crew knew the precise or approximate distance from one ship to their own) via a change of color in the red line used to show your guns angle. Also, you ask for your red line to be lockable so that you dont have to reaim when your ship heels or moves. If you look at the red lines possition in relation to the ship you are fireing at, you can already do this. The reason is said that what the admin is saying COULD be okay is that I understand that sacrifices are for the the betterment of the game(increasing the community size by making the game a little easier).
I am sad to see you ignoring the "beginner how to tips" that you need to learn at least one of them to solve your problem, i.e. using the red lines possition in relation to the ship you are fireing at. What the admin posted in not exactly your solution, as shown by my quote of your original post above. You want the game to tell you if you have a good fireing solution or not, istead of using ranging shots to figure that out for yourself. You also dont want to use your sails to alievate your heeling problems when shooting.