If they release a digic 6+ with the same kind of performance gains the 5+ saw, it will be very capable.
True, and then I would have been proven wrong. So that is why I am very interested to see what Canon puts inside the upcoming 7D2 camera.
As I recall, they didn't develop a new processor for the 7D, but rather used the same configuration as the 1D4. So maybe a new 7D would use the same config as the current pro sports model (dual digic 5+). However, those cameras came out really close to one another so that could have simplified the decision.
They may want to use a 7D as a test bed for new tech, or they may want to use the economy of scale and leverage of the existing production infrastructure.
In any case, my suspicion is that getting a capable core is the lowest hanging fruit in the higher resolution tree. Developing a line of great lenses is the biggest hurdle, and they've crossed it. The sensor unit is somewhere in the middle, and that's the biggest question in my mind from a tech standpoint, whereas the market is the overarching driver in all of this (if they don't think they can sell sufficient higher res cameras, they won't bother making them).