5DII is hardly an upgrade for a sport aps-c where a good AF and fps is required
A aps-h with the same spec as the current 7D - but with the AF, IQ and high iso would be an attractive upgrade.
Think of the L lens Canon would start selling - and also ease the path for dual body ownership
The cost of the body is significantly smaller than the cost of the lens and other acessories
I realize there is a lot of concern with 7D owners not knowing what their future will hold in the fields of sport photography... but shouldn't one use a 1DX for sports photography? And if they can't afford a 1DX, the 5D Mark III is also seen as a viable alternative for sports shooting. Especially with another FF body being added to the line up at the entry-level, I don't know if there would be justification to have two more prosumer aps-c bodies above the rebel line. Additionally, they are adding a 1DC to the FF line up as well... So maybe they will still keep an expanded aps-c line around in the future. But at the 7D price point, I think we might be looking at an entry level FF rather than a 7D successor. Maybe the entry level FF will have a decent continuous shooting rate but take cuts on ISO, AF (maybe keeping a 19pt), and IQ and resolution. It might be called a 6D???...
I am sure that the 1DX would manage for sports and at a pinch, birding. Not so sure that the 5DIII would be useful for anything more than occasional sports and birding use.
However we then get back to the issue of the lack of reach of a ff and the extra lens you need to achieve the same image.
The simple arithmetic shows that the 500mm:
- 1.6 gives 800mm equivalent
- 1.3 gives 650mm equivalent
- ff gives 500mm equivalent
I cannot imagine that a 7D owner with a 500mm used for birding would want an upgrade that would mean dropping $5k+ for the 1Dx and $10k+ for an 800 - just to take the same pictures. A 7D owner with a 600 would have nowhere to go.
It isn't even as if an 800 can be used with a 1.4 as the 1Dx doesn't support f/8 AF
The gap is very large between a 1.6 and a ff - what I am suggesting is that a 1.3 aps-h in a 5DIII shell would be an easy solution to help bridge that gap. It is proven (and good) technology that would give Canon a mid range sports shooter with significantly better IQ and low light performance than the 7D plus the proven potential to support significantly more mps.