Okay enough snowballing...I have to read some comic book to come up with my take on this. Accounting both feats of this ladies, I will give it to witchblade: to the simple fact it can adjust its level of strength, in fact it can draw out energy to augment its power and its wielder. Sara is no longer the whiny wielder and is more comfortable using the blade. Remember she was able to create a fortress and this fortress is within her control.
Imagine she can build a fortress around her and Diana thus trapping WW. Also a piece of the witchblade can act by itself and attack Diana invidually.