First off she's not so overpowering if anything I could see a lot of potential in her use later in Sarah /Sliverstar's backstory as for redrawing her I'd say play around with the idea a bit before committing to it  for example you could have it so VoidStar can use her abilities in her human form and save the Four armed Multi-breasted form for when she want to get really serious but give it a time limit or sorts..  
  
Don't take my word for it  and mentoned some very good points about the character development  I just figured I'd add something to it as well.