My opinion is that incremental improvements will become the standard with six month launches. This will be required to keep the competition at bay. Keeping the launch at a 12 month interval would give the competition to much of a window for PR purposes.
People will get used to the incremental improvement schema quickly after a few times when it becomes the new norm and will forget anything else.
I doubt a 6 month product cycle. It simply doesnt make sense, even from an operational point of view. What's likely to happen, is that they shift it a month or 2 backwards per iteration till they eventually hit the March-April.
For example, the ipad 4 was launched in Oct, the ipad 5 perhaps in Aug-Sept, the ipad 6, June-July, managing a 10 month cycle.
----------
I doubt apple will increase hardware specs unless there is a new feature that needs it...IPad 4 is twice as fast as iPad 3 on paper, but only marginally faster in real life..
Exactly my point, there is bound to be new features hardware wise or via iOS, and therefore its inevitable that iPad maintains its performance lead.