Not anymore. She has the Sparda sword, it doesn't get more powerful than that and it's her's now meaning that she is more powerful than Dante.
You make it sound like on a scale of 1 to 10 her lightning powers are a 1. She wasn't exactly a pushover to begin with. Yeah, adding voltage makes her more powerful but in terms of gameplay it's not very interesting in concept, just more voltage.
Yeah, but she could do that with any metallic object. It's the same concept of giving a dragon a fire sword: Yeah, it's fitting and it adds to the effect but if you see a dragon with a fire sword you assume he came with it but if you see a fire dragon with a a water or ice sword you know there is a story behind that and there are more interesting combinations to be had.