I basically agree with @HistoryWes in that I prefer my iPad3 over the iPad4 due to the change in port connector. As far as being upset because they updated the iPad3 to iPad4 way before the year was up, I'm not upset too much but I've got two concerns if they were to go to a 6 month release cycle rather than sticking with the 12 month cycle.
- Earlier Resale Value Drop: Whenever a product is updated the older version(s) drop in resale value. If they double the number of new updates over the same period in which you normally upgrade, then I think your resale value will take a huge hit. For example, if I would normally think about upgrading my iPad3 after two years to an iPad5 but found instead that in that two year time the newest was actually an iPad7, my resale value would be severally degraded. People are less likely to buy a version that is four upgrades behind the latest version as opposed to one that is only two upgrades behind.
- Earlier Obsolescence: Apple periodically stops supporting older models with new iOS updates, effectively putting them on the fast track to obsolescence. If Apple doubled the number of model upgrades over time it seems reasonable to assume your model will become obsolete twice as fast because it would soon be left without iOS updates.