UPDATE
So I decided to do some investigative reporting 🙂
I went to an Apple store, an AT&T store and a Verizon store to test out the display models.
In summary: ALL models were warm. ALL of them. However, some were warmer than others and in once case one model (Verizon 4G) was as uncofortably warm to hold as the model I bought (64 GB Verizon 4G).
While at the Apple store I spent about 20 to 30 minutes trying to get an iPad as hot as possible by turning the brightness all the way up and play youtube videos and playing games. It was warm but I could never get it up to the same heat levels I was experiencing with the model I purchased.
I made my way around the table and held all the iPads. I would describe all of them as warm, but not uncomfortably so. I did finally find the 5th model I tested very warm like I had experienced with the model I purchased. It was significantly hotter than all the ones I tested. It felts terrible to hold.
Lastly, I made my way to Verizon store. I found an iPad with the Verizon LTE service. The model was plugged in. I spent close to 1 hour downloading, browsing the web, playing games, turning up the brightness to 100%, connected and disconnected, it was even on LTE! But I could not get it to heat up. While it was noticibly warm, it was never to a point where it was bothersome or uncomfortable. Wish this was the model that I had bought. 😟
CLEARLY NOT ALL IPADS ARE CREATED EQUAL.
So with my testing, I concluded that it's natural for all iPads to get warm, but there is no doubt that there exists a percentage of iPads out there that get excessively warm or even hot. If your iPad gets overly warm where it is uncomfortable to hold or worse yet shuts off due to excessive heat, take it back before your 14 day return window expires. This is not normal behavior.