You mean the Hexblade?
The best fix, in my opinion, would be to give it full casting, starting at level 1, like a duskblade with a differently themed spell list. If you still want it to be a slow caster, make it more like a bard, only going up 6 spell levels. Also, give it medium armor proficiency and casting in it. Keep everything else the same, I would say.
Also, more hexes per day, make the hexes scale better, and make them not expended on a failed attempt.
I'd play it.