The first LTE tablets -- presumably from Motorola and Samsung -- will hit the market in July or August, both on Verizon, for starters. Considering that LTE smartphones are already on the market, making an LTE tablet is relatively easy: less battery concern, and no circuit-switched voice complexity to bake into the overall mix.
What does this mean for Apple? With multiple LTE tablets in the market by the end of August, why wouldn't Apple make an LTE version of the iPad by September or October? I don't see any reasonable engineering obstacle for this.
Doubling the iPad's screen resolution: As with LTE, everybody knows this is coming -- it's only a matter of when. Samsung has stated its intent to double its large tablet resolution some time in 2012. I doubt Apple would be able to do so much earlier than Samsung, and it also takes a new more powerful processor to drive such a high-resolution display. It is therefore unlikely to happen this year.
NFC: Research In Motion (RIMM) will have NFC in its 3G and 4G PlayBook tablets in the September-November 2011 time frame. Google will probably have it starting in November and onwards. There is no good reason Apple shouldn't also have it by this September or October.