I don't think Aranea is comparible to Vriska until she kills someone for her plan. I don't think what she's doing is bad either. She wants to be a hero. More importantly, she thinks she can do this, and is the only one who can do this, so why not take a chance to be a God Damn Hero like she's always wanted? At least she's not trying to create Lord English so she can have a showdown with him, like a certain ancendant tried to do.
Also holy shit she can DO that?
Frankly, I'm surprised more people aren't talking about something she just revealed casually in passing: