Knockback is desirable on a melee character. Just because you frequently want to be adjacent to enemies doesn't mean you never want to be away from them.
My comment about knockback was referring to Quake as a AOE attack. Knockback could be desirable effect for defensive purpose, but it is undesirable for offense. And even if you want to be away from adjacent enemies, Quake might not be a good option either, because it might land you at a worse position. These leave me thinking that, Quake as a:
Offense option: At least we need to remove the knockback to enemies and the random position shift to self, and potentially like what Davion Fuxa said, add it with a battle call like ability to draw them 'too' (which could be selected?)
Defense option: At least we need to remove the random position shift to self, and potentially like what I said make it a sustain which let you have more control over the terrain formed. I always feel this terrain re-arranging ability could be emphasized more as it is the main flavor of this talent. It could actually be made as a preparation move before battle (maybe also let you choose the radius?), and you lure enemies into a terrain of your choice
A mix of offense and defense option: At least we need to remove the random position shift to self. Potentially remove knockback to enemies and replace it with other short duration status effect so it won't hurt the offense side so much. Other tweak mentioned above could be applied as well
So it appears to me this random position shift to self need to be removed at least