I abandoned my Leviathan in favor of a DA because so many people told me to ditch the former and that DA was, hands down, the best sword in the game. I'm not impressed by it, honestly. It's slow as hell and looks like a giant yellow [pointy thing]. I actually did better with Levi in FSC.
So why is this weapon loved so much? Did I make the right decision making one?
practice to always 1. use charge 2. first swing -> shield. Then use second swing only if you know you knocked all enemies close to you that they cancel their attack. The best thing about heavy sword is that you can swing 2 - 4 monster at once, hence you can create safe distance always.