JRosen wrote:
If you can't see it, you surely can't shoot it! As one of our colleagues mentioned, the glass is to see, the camera is merely a recording device. Why not rent a good piece of glass with your current camera body, and see if that gives you the desired shots you are looking for. If not, then rent a body and see if that scratches your itch--or both.
This might be a good suggestion. You would need to try shooting wildlife with it. But then you should also try shooting some of your wildlife pictures with a camera that has a more up to date focusing system.
The focusing system might involve a learning curve, so the rental might be a little long. By the end of the rental period for the lens and camera, you may have spent your upgrade money.
But honestly, your lenses are quite able to pull most of the potential from your current camera. If you were just shooting landscapes and not wildlife, I would probably lean toward a new lens, but the wildlife part pushes toward a new camera with a better focusing system.
The 70D gets my vote.