Ask a Magician Thread.

Paralyze does 620% @ 810ms + 160%/s DoT.
Big Bang does 290%x5 @ 810ms + <1000ms charge.
Paralyze: 765%/s + 160%/s DoT
Big Bang: 801%/s and I'm fairly confident they reduced the charge time for Big Bang to something like 600ms, unless they reraised it in Big Bang.

My point was that Paralyze's base DPS was lower than Big Bang; once you've gotten the stun and DoT off, Big Bang is better for DPS.

Big Bang takes a full second to charge (I think it's 1040 ms, to be exact). It used to take 2. Plus, that's assuming you're releasing it as soon as you finish charging. Paralyze being weaker on a single target would be really bad design.