Basically, the idea was that fighters in elaborate outfits are fun, even if they aren't the most practical. It would be cool to encourage people who felt the same way to go wild with their imagination. However - I also think gritty, realistic and/or clanky armor is cool too, so I wouldn't want to make that worthless in the process.
Jeff characteristically came up with a simple and fun rule for this - any Fighter in such a costume would get the equivalent AC of Chain Mail. I like that; its not the best armor class, but its respectable. There is still a reason to put on that magical armor you found or work for something like plate armor.
I'd like to up the ante a bit though, since my games have some penalties for wearing heavy armor that most B/X style ones don't.
Said outfit will give you an AC bonus of +4 in Barovania/Akenia if;
- The outfit is elaborate and conspicuous enough that it will be recognized instantly when seen.
- The wearer is a Fighter, Murder Princess or Battle Princess
- If a shield are similar object is incorporate into the outfit, it is cosmetic and does not provide an AC bonus. Magical shields may provide other effects, just not the increase to AC
- The character wears it constantly, or at least whenever they fight. The outfit should be a big part of their personal style and maybe even their identity.
- The character may wear other clothing over top of it (perhaps for a disguise) but the second that danger is a foot or a fight begins, they should throw off their disguise and reveal themselves properly. They may attack OR move while doing this.
- If the Character has an opportunity for a surprise round, they may sacrifice it and instead announce their presence with some sort of speech and a pose. This grants them a further +1 to their AC in combat. Here's an example.