Swimming in the sea is the feature that I'm most looking forward to, so I may get the patch first, and wait until after Christmas (when it's likely to be reduced-price) to buy the EP... or otherwise drop heavy hints to my loved ones, about how awesome this EP looks, and how snow is absolutely, completely essential to a story... It looks like an amazing EP though, and I think it's going to add a *lot* to gameplay - as KJSinclair said, a lot of diversity. Which I'm a big fan of in almost every context, but in Sims3 gameplay, even more so!
I'm surprised that wild swimming is only allowed off-lot though - does anyone have any ideas (e.g. the way that sea behaves on a lot, as I've noticed it looks slightly differerent over a lot) as to why this is? It means that, slightly bizarrely, Sims can swim in the sea, but not if they go to a beach...