I'm sure there's going to be an iPad 4 next year so I'll be waiting for it. That said, I wonder if this "mid-year iPad spec bump" going to be a trend from now on or just a one-time thing to counter Microsoft's and Google's launches this year.
I was stunned to hear they did a a regular iPad update. To me, that means 3 scenarios are on the table:
1) It was a one-time chance to present a united front for the holidays. They get lightning on all of their products, kill 30pin, and let iPad Mini lead the way into Christmas. We still see a new iPads chassis mid next year.
I think this scenario is not very likely. If they really wanted to keep the iPad march schedule we would not have seen 4th gen today. Certainly Apple is taking advantage of the united front approach but I'm willing to believe that the March conference schedule is now dead.
2) They used the iPad mini in part as a way to buy time and stretch out next-gen iPad development. iPad chassis updates now occur every October instead.
If the only way to reduce weight and frame on the iPad is the battery, then it's likely they are stuck waiting on an A6X die shrink (lower power consumption -> less battery needed) which perhaps is not in the cards until late next year. So I think this is plausible, if only to reach iPad 2's weight/frame again.
3) The iPad has been transitioned to a product update schedule as with Macbook or iMac, meaning Chassis updates could be 2-3 years apart from now on and for most October conferences we can just expect spec updates.
This, on the other hand, is also very plausible. There isn't a big laundry list of changes for the iPad frame to make. It's too big for a glass-sandwich approach and the resolution isn't going to change anytime soon. It could slim down more and cut weight, but both of those are dependent on the battery. So it's entirely possible they take their sweet time with re-invisioning what the iPad looks like and we just can look forward to a series of spec bumps for the next few updates.