What's next? The answer is not determined by camera specs, but by price point.
The next camera should be in the $2000-$2500 range to fill the gap. This could be a 7D with slight improvements to justify the price bump. A continuation of the 5DmII with or without changes to it to be an "entry level" FF. Or, something new.
Whatever it is, don't expect any "leaks" until about a month after the 5D3 has been shipped.