Well, we already know by the photos on the press release that the surround cameras are definitely going to be more useful, with the two front ones pushed out to the corner of the bumper and renamed "T-junction cameras". As mentioned in another thread, the present position of the two front cameras on MY2013 and earlier renders them pretty useless to spot anything other than what's in front of the car (and you don't need cameras for that... You can just look through the windshield, lol.) I have wondered if I could go to a shop and ask them to move the front ones on my car to the same position where the 2014s are going to be mounted, it can't be that hard as it's only a few inches.
A Nav update is doubtful - other than more up-to-date maps and POI database - although new tech introduced abroad, such as Blind Spot Monitoring and Reverse Traffic Detection, may make it to the US market on the 2014s since it's being used by most other premium auto makers already... More esoteric stuff, such as the Wade Sensing "sonars", wasn't included on the recently released NAS version of the 2014 RRS, so we most likely won't see it on the LR4 in North America, either.