FWIW, weighing in on the 2012 vs 2011 Oly debate, I have some hard data on the swim, as I measured both with my gadget (not using Garmin's inaccurate 'swim' function!) - 2011 came in at 1690m and 2012 1550m. I certainly felt that when I reached the turn this year that the flow was much stronger than last year. Putting it all together, I think PK is correct in calling the swim 'course' to be faster this year - about 3m seems right to me. I also think using the likes of Luddick and Earley makes sense, as these guys are well-established metronomic swimmers, who have been at the top for some time!
On the weather, while the temperature this year was probably similar, it was definitely sunnier (how many people didn't get burnt last year, I certainly did -
?), but maybe more humid this year. Last year certainly felt more draining to me!
So, to compare 2012 to 2011, I think you need to subtract 3-4m - having said that, I certainly agree that standards this year are generally higher. There are some very impressive results around, not least from the guys (and gals) populating this forum, so well done all!