Upload & Sell: On
IMO, it depends on the type of wildlife and the limitations of your lenses. For example, if you're focal limited to 500mm and want to capture songbirds in decent light, the 7D (or newer 70D) is (are) best--not even close. Pixel density makes it so. In many other conditions, e.g., longer lenses, bigger wildlife, BIF, or in lower light shooting, the 1DX, 1DMKIV, and 5DMKIII are better choices, each having a slight edge depending on the particular circumstances. Obviously (I think), the 1DX is the king in the overall sense.
Oh, I hope I haven't stepped in it.