i'm much more excited about the Sigma F2.
I'm extremely tired of companies offering very small incremental changes over longggg periods of time. I'm not holding my breath for Canon to release what I want, I'm just moving on.
They easily could have made the 24-70 2.8 II an IS lens to begin with, which we all wanted and expected, especially for the price. Had they made one, I probably would've bought a 5DIII and that lens(Instead of switching to Nikon who's 24-70 is amazing.)
At this point in time, I'm much more excited about 2.8 zooms and cheap bodies for the EOS M and a FF mirrorless.
I would not pay 2500 dollars for another DSLR lens as I'm very tired of the weight, and I'm not a pro. I'll probably just hold out and hope Sony can make a 24-50mm 2.8 in a size smaller than current 24-70 2.8's for the upcoming full frame mirrorless they're announcing.
Just an FYI based on insider info Canon was testing several variations on the 24-70mm IS. Due to Canon's choice of image quality criteria the prototypes were unreasonably large and heavy. So Canon opted not to release them because they thought they would be too oversized.
Tamron was able to create a 24-70mm 2.8 IS in a small size because they compromised on image quality.
To get around the fact that a fast image stabilized lens would be huge and heavy Canon even considered a 28-70mm f/2.8 IS.
The 28-70mm f2.8 IS would have had a filter size of 86mm. The 24-70mm f/2.8 IS would have had a filter size of 95mm based on Canon's patents.
The lens would have looked something like this:
That's a Nikon 14-24mm with a 95mm filter which matches the dimensions of the Canon patent.
I personally begged Canon to release the prototype.
Also some people suggest that Canon didn't release it because it would have a low profit margin.