.... 7d2 ... is not a revolution of technology, so its hardly a gme changer.
But a7 is.
First ff mirrorles. Yep i know about leica, but its too exotic and pricey
A7r offers really nice sensor in a compact body
And a7s low light performance is incredible. In a light and small package.
A7ii first ff ibis.
And they can easily use canon lenses with af. You can call it a first step to universal lens mount if you want.
Im not a sonynfanboy, just a general phot shooter and a7 looks very promising to me
Disputing the meaning of "game changer" seems pointless to me (and regardless of whether it qualifies, I have no doubt the 7DII is excellent for what it is), but regardless of that I'm very partial to the Sony a7 line myself - I've owned an a7r for almost a year, was impressed by the a7s I recently rented, and am tempted by the a7II. However, to say that "they can easily use canon lenses with af" is highly misleading. On these bodies AF doesn't work at all with some Canon lenses (and may not work at all for most third party Canon-mount lenses), and when it does, while accurate (no AFMA required), it's slow - so slow that it's useless on anything that isn't essentially motionless. Much of the time mf is faster (though mf just works better with lenses designed for mf rather than af).
So far, these cute little Sonys seem to me to serve a fairly specific range of people - those prefer small camera bodies, prefer mirrorless, don't need long/fast lenses and aren't much interested in sport/BIF photography and/or prefer using old (or indeed, any) manual focus lenses. I have no idea how big that range is (it does include me...), but it may be rather small, esp. the mf lens subcategory.
As for Canon ripping us off (as someone put it) by putting IS in lenses only, just how much cheaper would the already cheap 10-18mm lens be without it? Does anyone know what proportion of the price of the 24/28/35 IS primes is attributable to IS? I wish every Canon EF/EF-S lens had it....