Well, there a few pros and cons going to 70D from a 7D. But some people consider the pros important enough to make the move. Personally, I pass.
I pass too. 2MP more? I would like 8MP less! Not going to happen though.
Also, and I hate to give DxO much credence, but assuming their testing is at least consistent between generations then their stats don't suggest a massive IQ rationale for an upgrade.
The phase AF systems are different, 7D much more control. I like the flip out screen for video, but I've got my T3i for that, where for me, AF isn't important.