Building off of what jonathancrazyj said, I didn't want Berserker to be situational for OTK decks, which is why I tried to re-balance it by adding the drawing effect in its ability.
I'd make it Fire, but the main feature of Berserker is the unavoidable (therefore, momentum) burst damage. Heck, I could even make the ability cost Time, since you're drawing a card, but all the mechanics (accelerated draw speed, momentum, increase in attack for a decrease in defense) either have connections to mechanics that Gravity already owns or connections to force, acceleration, etc.
Thanks for the positive feedback, although the karma wasn't really necessary. This is just another card idea. ^^