While a 7d3 will be much more advanced(although I don't expect as big of a jump in image quality compared to the II against the original), it will be much more expensive as well, at least 2000 usd if not more depending on its features.
Like Don Haines said (in another thread): "
You want the features, you pay the dollars....".
Those photographers that, like me, want a truely very capable
top-of-class cropped action camera from Canon, cannot expect it for the current price of the 7D Mk II. That is a no-brainer.
For the 7D Mk III to actually be the improvement that I and perhaps other
cropped body action photographers want, it needs to become substantially more expensive than the current price of the 7D Mk II.
The price difference between the D500 and the 7D Mk II has been around €700 for a long time. This price difference means that many starting action photographers will choose the 7D Mk II over the D500. Canon just competes on price, thus avoiding competition on performance/the product. Hence there is no incentive for Canon to improve on the 7D Mk II, it sells itself. And who can blame Canon for exploiting this: they are in the money making business, not in the please-the-customer business.
Therefore I even hope that the 7D Mk III will be in the €2000 price range. Just like the D500.
With a 7D Mk III costing around €2000, Canon cannot simply compete on price.
Then Canon would have to compete on performance to sell the required volume.
With Canon’s technology and experience, I have no doubt that the world would then see a top-of-class
cropped action camera where it really counts: in AF and sensor performance.
And if this wish would come true in 2019, what a fine year that would be!