I've heard the 2012 models are on the way to US dealers, but I don't know how this relates to their arrival in NZ. Since nobody has one yet there has been no "real world" ride reports. Boat test has done a review for whatever that is worth:
YamahaFX Cruiser SHO (2012-)2012 Reviews,performance,compare,price,warranty, specs,Reports,Specifications Layout, video | BoatTEST.com
Looks like the new bigger hull on the 2012 has not lost any speed, but does burn slightly more fuel. I would suspect that the 2012 hull would have to be a little more stable in rough water if for no other reason than the increased length.
New features like the external storage compartment, and external flush port are nice improvements, but not enough alone to sway me to buy the 2012. The mechanical neutral is also nice, but with a little practice you can maintain neutral on the older models by holding the reverse bucket 1/2 way. I think we will just have to wait and see what the price difference is between the 2012 and 2011 models, and see some actual ride reports. For me if the price was more than $700 I think I'd stick with the 2011 model at this point.