Hullo Hjalmarg1, seems there are a lot of people asking the same question as you are. I have quite extensively compared the ergonomics and performance of the two cameras, 7D and 70D, on my website. Here is the link http://www.grantatkinson.com/blog/canon-eos-70d-and-canon-eos-7d-compared
In summary, the 7D has a bigger body, more robust, with more external controls and a slight speed advantage. The 70D has an image quality advantage, in good light and especially at higher iso settings, perhaps a slight AF improvement, a definite AF improvement in Live View and video in a much smaller package.
Hope that helps
In most disciplines the 70D is better than the 7D.
If you do shoot in extreme situations the 70D will be the "better 7D"
Mr. AE1Pguy is right too, if he prefers the 6D. In speedy situations the 70D is better and has more AF points... But the Eos 6D-IQ ist far better than the 70Ds - especially in low light situations.
(My personal opinion)