It does, somewhat; a lot of Shaman go Enhancement because Elemental is performing so much worse. It's not as easy to switch, so if a patch suddenly hosed Enhancement and boosted Elemental you wouldn't see as fast a turnaround, but it has a long-term effect.
That's just why it'll take a few weeks/months to see Elemental's true recovery once they're fixed, though, as people gear up their Elemental spec again, not an explanation for their current numbers.
Because "top X parses" is statistically dishonest and misleading for a host of reasons, always, regardless of the amount of data. In fact, as you get more data, it makes "top X parses" models MORE misleading, not less.
I dealt with this in excruciating detail in a blog post a while back. The specific numbers are obviously out of date, but the math theory that is the point of the post is math theory, and never goes out of date;
http://www.mmo-champion.com/threads/880800