Just got a new ipad.... Holy crap apple. Under the covers Apple is a mess. Mainly the lack of any options and no file browser on iPad. iTunes, don't even get me going. I read this article and tried several things to get rid of the raw files.
I'm Importing with the USB connection kit to an ipad air on ios7. Nikon Raw and jpg files on the camera. If photostream is on I get a jpg only slight resized into photostream and a raw and jpg into the import folder. Almost okay, but not good enough.
I bought the full version of FileBrowser and I think I have a workflow for somewhat large quantities. Import with photostream off. In filebrowser make a copy of only the jpg files (use the select list to do it to large numbers). Once a local copy is in filebrowser, copy those to your camera role. Then delete the imported file in my photos from the imported folder. Delete the extras from file browser. Turn photostream back on. Royal pain in the ars....
That will work for vacation, but for studio work I'm thinking camer ranger or an eye-fi.