well...there are different styles of hoods available and although nwn didn't give helmets that let you use your own character's face, there are some that do have faces.
I've seen a widget used on another server that lets you put a helmet on, apply the bonuses it gives, then remove it and keep them active so I know that's possible.
I'd like to see an option for an 'invisible' helmet added to the appearances like the 'invisible' cloak model but someone once told me that wasn't possible although I'm sure I saw an 'open-face' helmet on one server, I just forget which one so I can't check.
I wonder if the hat models could be used for helmets instead ? I know i've seen them as both robes ad cloaks but I don't know if they can be helmets or someone already would.
One thing to remember, is that in medieval times, people wore hoods almost all the time, even without cloaks, although their faces were still visible, like a winter coat's hood today.
All that said, I'm willing to take my sorceress's hood off if all the fighters will take their helmets and boots off.