I'm glad to have buy a new 70d for 892 € (and don't wait for the 7D II) and be happy about how it performs !
If Canon take too long to announce 7D Mark II, people will buy 70D. I'm just warning you
Canon 400mm f/2.8 IS II is 11K. I think the reasonable price for Sigma 400mm should be about 6K if the IQ of it is close or equal to Canon version.
According to the owner's manual, a 7D version (N) lacking WIFI capability is planned to be available. The 70D version (W) is the specified WIFI-capable version – this is the only model I've seen available here in the USA.