GFCI devices must be installed in a readily accessible location (This impacts ceiling garage door opener devices).
The tables in 310.15 & 16 have been rearranged. Now you have your Ambient Temperature Adjustments separated into their very own table.
Transformers now require disconnects on the primary side. Now transformers fall under very similar rules that we see for other equipment.
Tamper-resistant receptacles are now required in guest rooms and in child care facilities. This increases the TR rules in most areas now.
Neutral conductors will be required at switch points, though there are a couple of exceptions, including where conduit is the wiring method.
No Grandfathering: where replacing a receptacle that would have to be AFCI, tamper-resistant, or weather-resistant, according to the 2011 code, those types of receptacles must be used in the replacement.