I have no idea if anybody has ever suggested this, as my browser takes a poop every time I try searching something on the forums.
Different fighting style upgrades. As in, you set yourself a fighting style, which gives you bonuses towards certain weps. The idea is, to reward the player for choosing to stick to his favorite weapons.

By fighting styles, I mean "offensive" "generic" or "defensive".
Defensive would give you bonuses on guns and bombs, and shields while offensive gives you sword and bonuses on offensive geared armor like mad-bomber, and wolver line.

Have fun disputing and suggesting.

Cheers.