Hide helmet is where powergaming meets roleplaying :P PLayers want to have their character good looking, but do not want to loose some deffensive stats.
Personally, I don't like invisible helmets and would not use such feature.
The best solution is complicated to implement - IRL knights wore helmets (and armors) only during battles. It could be achived in game by unequiping those while in town, but it is too much micromanagment to be fun. So it could be automated by programers.
But it is a little harder in a game with no "safe area" - should armour magicly appear as soon as you start bar-fight or not?
Or maybe it could be programed with a hotkey (and if supriiced with fight, suit up would take yor AP)?
I am also no fan of invisible gear and made my comment with a tongue in cheek as it does not matter much as feaure in a solo/co-op game for me.
But I do like your simple compromise solution, instead of making them invisible an to save people the awful micromanagement it would be neat to have a simple button to take the helmet off and put it back on when needed. If people forget it, their problem. But at least they would wear the thing when it matters and not turn it invisible and then, as usual in most cases, never let it re-appear in the field.
And if people want to charm others or intimdate them they can decide themselves if they have a better chance with or without a helmet on.
Damn...I should post this to all those MMO forums as a hotkey helmet on/off would make more sense then to hide it in some option sub-menu.
Latest when they get one hit on their noodle (and survive it) they will learn to put the helmet back on even it will cost them still one push of a button, but it is at least their responsibility to remember it.
When they ask for lack of convenience then they should be glad not to be asked where they carry their helmet if it is not on their head as it will just be in their bags like all the other nicknacks like makeup kit and body oil.
