Based on Canon's strategy, I don't think so. What kind of specs do you have to cramp into 70D to make it earn the moniker of "5D3's crop equivalent?"
It will be difficult. 5D3 is the only DSLR that has the same AF system as it's flagship DSLR. There is only one other time a Canon non-flagship camera having a flagship camera's AF system but it's in the film SLR days. When it was launched, many agreed that the line between the 5D series and 1D series has closed up significantly. The same AF system rumored to be on 7D2 has yet to be confirmed and even it's true, I see the reason behind this strategy as explained in my previous post.
It will be quite difficult to see a 70D which specs so good that I can call it the 5D3's crop equivalent. Just look at the 6D - how much Canon has taken off from the 5D3 to make it an entry level FF camera. Do you think 70D will have the same 61 AF-pt system? I doubt so. Same level of ISO management for an APS-C? If 7D2's rumored ISO improvement is true, then I doubt 70D will be as good as 7D2 in order not to cannibalize on 7D2's sale. There is still a chance since if 7D2 is possible, then technologically it can be possible for 70D, but if Canon wants it or not.
What about swivel screen? It's a big selling point of 60D. If 70D keeps this feature, then weather seal is compromised. Dual card slots on 70D? I doubt so.
I think Canon has always been clear in their product segment (it's a double edge sword). Even for the 5D3 - on paper it doesn't seem to be a big deal compared to 5D2, but 5D2 and Canon users will understand it's significant improvement once handling the 5D3. It may not be much, it is usually not much, but sufficient enough to address the concerns of its users and will stop at a point to prevent cannibalization of sales from a higher end product.
Same goes to 70D - personally, I expect Canon to bring it back to the expectations of previously 50D users, and maintain it as a XXD line of product only, and maintain at that level of pricing.
And don't forget - 7D line is supposed to be Canon's King of APS-C - they won't be so stupid to build a 70D that kills both 7D line and 5D line sales.
+1 to your comments.
+2 to your comments except for one small change...
I think that the 5D3 is a big improvement to the 5D2. What was lacking in the 5D2 was a robust AF and all the technological improvements seen in the 7D1. The introduction of the 5D3 more than compensated was what lacking in the AF of the 5D2 with 61 points and one of the best AF systems in the industry. Instead of Canon catching up to Nikon in the AF department, it is now Nikon catching up to Canon. The Lens Rental tests makes this very clear with the lack of standard deviations well in favour of Canon.
Another huge improvement in the 5D3 is its low light capabilities. Again, this is something that Nikon cannot replicate with its D800 model.
Add to the above huge improvements are all the little improvements made to the 5D3 that were introduced with the 7D1 but missing in the 5D2. The total package make the 5D3 one of the most sought after cameras in the industry.
One last improvement which gets very little mention by anyone, is Canon's obvious commitment to quality in the 5D3 model. While the Nikon suffers from focusing issues and green tint problems, the launch of the 5D3 went relatively unscathed. The only small issue that came up was the light leak issue which in the real world did not affect the IQ of photos in any significant way. Despite this, Canon was on top of it asking people to have their cameras modified to eliminate this issue altogether.
I believe that the 5D3 was a godsend to Canon users and for that matter, the entire market in general. It will be regarded as an industry leader for quite some time.