Again, have to disagree with your justification for a February announcement. Take the iPhone 4, announced on June 7th, available for pre-order a week later on the 15th, launched on the 24th June and that was with the Retina display. The only time Apple need to pre-announce something a month or more in advance is if there's a new hardware function that MUST be supported at launch, in the case of the iPhone that wasn't the case as existing apps could scale up without any problems.
Look at the list of potential features for an iPad revision: camera support is already in the SDK as it multi-threading support if they go dual core on the processor. An increase in resolution would only really make sense if they double resolution width and height which can be dealt with by the OS with no coding changes. Gyroscope compatibility is already included, SD support (if they added a slot) is already included (just treat the slot as an adaptor)... what is there that would REQUIRE a new SDK and time for dev's to get to grips with it? Add on to that the impending release around April of iOS5 beta and I just don't see it happening, sorry.
Our estimates about the time between announcement and shipping don't diverge very much, actually. I said "~4 weeks", and your example is 2 1/2. And the other iPhone launches were longer than that.
I also agree that many of the rumored improvements wouldn't require much from the developers, but so what. At some point Apple *will* surprise us with features we weren't expecting, at that developers need lead time for, right?
But Februrary, March, April, whatever. I'm just wondering if anyone else sees the need for a holiday refresh.