@Helperman
con is absolutely right. Have you thought about why the hud options are placed in the difficult settings and not in the graphicoptions? You need to see all sides of the coin.
Making Hudfeatures optional in the graphicsettings a server won't overwrite it. If the servers won't overwrite it there would appear a huge disadvantage for all verteran or expert players who play competitive missions on publik servers and even their own ones.
Example: Playing with Crosshair, 3rd person, playermapmarker,waypoints, etc against others without Crosshair, 3rd person, playermapmarker, waypoints, etc on same server... would be very unbalanced, isnt it?
Serverside Options forces all players of the same server to be on a level playing field. Clientside options wont and will never do that!
You say give us the options to decide it ourselfs and you said you are an ARMA player since years.. than why you dont know that you already can decide it yourself. The following also includes your hypothetical example.
Join the server give yourself a vote as admin (right SHIFT+P), go to the servers mappool and start him with difficultsettings you and your mates want or start a map- and difficulty-vote (like recruit, veteran, etc)? Its one of the reasons why you have a votesystem!
Or host a own server with cockies and your custom difficulty settings, which you changed before in the gameplay options.
I really don't see any need to chance hudfeatures from here to the graphicoptions in ARMA 3. Coz since OFP all these things are full customizable for the client and the host. If you can't arrange with other player about the settings its your problem, but you might be the only one who can't.