EA Sports put up the first screenshot of NHL 11 on the game's official Facebook page, intending to drop hints about what it'll deliver. From the details of the frame, it looks like a new physics engine and broken sticks.
"All-New Real-Time Physics Engine in NHL 11" is the caption to the grab - manifested in this unidentified Blackhawk's asscheck of Pens winger Chris Kunitz. The broken stick adds a small touch of realism not accommodated until now. Obviously, that means EA Vancouver will have to program players to do something without them until they can get back to the bench for a new one.
Other commenters have said the arena background is upgraded but if so, it's a little subtle to me.