I did a blog post about a few weeks ago discussing superhuman INT and how it can have cool effects in play. I liked how this brought new options in play for characters with superhuman ratings in what might be considered a 'dump stat', and I wanted to do the same for the other perceived dump stat, Charisma.
Charisma reflects the power of your personality, and how you can exert your influence upon others. While mechanics exist that tie Charisma to traits using manipulation (an important first step in making less dumpy), I'd like to do more with it. The groovy gang on the Splintered Realm Community got me thinking about this, and I've since clarified it a bit more... this is another something that will eventually make its way into the GMs sourcebook....
Since half of your hit points represent willpower, determination and mental toughness, it seems reasonable that this 'half' of your hit points can be attacked directly in ways that diminish your willpower or directly impact your mental toughness. CHA is the solution.
Superhuman CHA gives you the opportunity to deal damage that comes off of the half of hp representing willpower/determination. I think of the dragon Smaug and the power of its personality 'wearing down' Bilbo over time through its wordplay and manipulation. You'd be able to deal up to half of a creature's hp total in damage through 'CHA combat' in this way. With exceptional CHA (14+), you can use 1 round to deal social damage equal to your CHA rating. The target may roll a FEAT for half damage. A target will never take more than 1/2 of its hp total in such damage. You can do this a number of times per turn equal to your LM.
For example, Lex Luthor, with CHA 16 and at level 10, can potentially deal 80 hp of social damage each turn, as he stands back and tells Superman what he's going to do to Metropolis, how he's going to scar Lois Lane's pretty face with acid, how the Daily Planet is going to become the Daily Luthor, and how he's going to scour space for the remains of Krypton and poop on it. Meanwhile a bunch of Luthor bots are beating on Superman.
I'd also like to introduce a new Talent, Taunt, that allows you do either make one bonus attack per turn (if you have CHA 14+) or take on this special application of CHA even with CHA 13 or lower. For example, Spiderman has CHA 9 or so, but with Taunt, he can get under the skin of Doc Ock, badgering him during combat, dealing 9 points of damage with each taunt.
Using you CHA to make willpower attacks in this way would be a minor action, meaning that you can do this and take a simultaneous attack at -2. Spidey can jaw at Doc Ock while also firing webs at him, taking -2 to the simultaneous attack action.