Tim did not promise an update to the MacPro. That is more what media and fans have read into his words. What he actually wrote was: "[...] Our Pro customers like you are really important to us. Although we didnt have a chance to talk about a new Mac Pro at todays event, dont worry as were working on something really great for later next year. [...]"
Now i'm no native speaker, but to me this is remarkably unprecise - "something really great" is not the same as "an update".
They may completely ditch the current platform and go for something like a 64-core machine based on a couple of A6(X) ARM processors. Cheap, because millions are sold in iOS devices, and slowly gaining power suitable even for desktop uses. Proper "pro" use cases usually assume multi-core awareness in the software, so more cores = better. Certain crucial software components are already there, like Grand Central Dispatch in OSX, which is working independently from the actual number of cores.
That way Apple could not only losen their dependency on Intel roadmaps, but also differentiate themselves better from the rest of the WinTel market. IIRC there already have been rumors about Apple investigating other hardware platforms, although they have been associated with "low-performance" (in comparison) machines like the MacBook Air.
But in a suitable desktop housing the size of a current-gen Mac Pro they could center some serious CPU power if done right. (If you believe in conspiracy theories, then maybe the delay in updating both the mini and the iMac is related
) They may as well get rid of the old housing and replace it by stackable modules re-using Mac mini housings to allow for easy (not inexpensive - it's Apple after all) performance tailoring and further leveraging of economies of scale.And this may also be the time when they announce the merge of iOS and OSX: why separate those when the underlying hardware is basically identical? To be honest - during the iPad mini presentation, when Phil had the iOS icon on screen next to the OSX icon, for a moment i really expected him to announce the merger and show an animation of how those icons merge into a single one.
That hypothetical new machine may not even be called 'MacPro' anymore...
