my thought was that in a winter deck your more used to flipping it at 13, a non winter deck might not realize (as i did) that he gets the benifit too, so would wait till 14 power. i'm still not sure its going to come up all that much, but it has some interesting quirks.
Wolves of the North Cards
I like "Winter Festival" simply because it's a plot with an effect I haven't seen before. I'm always looking for new and fresh ways to plot (pun intended) my strategies for my decks.
I can think of many times where I was only one or two power away from winning and just could not get a challenge off due to various reasons. This plot will win some games for some folks, I have no doubt.
Hope to see some more new plots in the coming CP's. The reprints are nice, but I enjoy seeing new stuff like this too.