Titan fighter seems busted, what are the penalties?
A 2d6 greatsword averages 7 damage while a 1d8 longsword averages 4.5 damage. You're basically taking an additional -2 to your attack rolls on a two handed character to gain 2.5 average damage. That's a net negative IMO.
The main advantage I see is that you can make a two weapon fighter that also has reach thanks to having a fauchard. I doubt this is stronger than just normal two handed fauchard usage though.
EDIT: To be clear, the reason two handed fighting is good isn't because two handed weapons are better, it's because two handing gives you a 1.5x strength and 1.5x power attack bonus. Wielding the two handed weapon in one hand loses all that, unless Owlcat massively fucked up.