Back to the original question..."Will Apple ever made one for iOS? Look at how Adobe did with Lightroom mobile for iOS?"
I surely hope not. I routinely take my 15" rMBP into the field to capture images from SDXC cards, do initial culling and editing. The rMBP has a 15" calibrated Retina screen, quad CPU, dedicated GPU, 16GB of memory, a keyboard, trackpad and ports for a mouse or Wacom tablet. And it has Aperture, LR, and many plugins. How will you get the Nik Collection, Perfect Photo Suite 8, DXO Optics, PSE, or PS6 or other plugins installed and working on your iPad? Using the iPad assumes the editing capabilities in an LR or Aperture are sufficient for all your editing needs. Not.
But trying to use the iPad to seriously edit photos is just slightly better than trying to do that on an iPhone. 😉