I had the same problem, I have just over a gig free on my 16g iPad, I literally cannot delete anything else otherwise I will be deleting actual business data, even though I store allot on DropBox and Google drive I still need to have info such as videos on my device to show clients, so I guess I will not be updating to iOS 8 until I get my new Air which will have iOS 8 preinstalled. But then I am going 128g or 256g if it comes out, lesson learned!