It wouldn't surprise me if Apple revised the iPad with the new dock connector so that all the iOS products switched at the same time.
If that happens, it also wouldn't surprise me if they made some additional revisions at the same time. Not sure if that would go so far as to switch over to the IGZO screens that were rumoured to be wanted originally in the 3rd generation, but I wouldn't rule it out.
I think the annual revisions have become a bit of a chain around Apple's neck. I think they would like the flexibility to update when new tech and designs are ready. A small update out of sequence could be a good way to test the waters for flexible update times.