No, of course not, but how many times do you see bad changes? Or a player stepping onto the ice and then a goal is scored against their team? The game is so friggin fast, and a 30-45 shift means players are coming on and off the ice all the time.
I'd love to see a statistic that included changes. I'm pro statistics, believe it or not. Information is good. I don't come to the same conclusions that you do, and to each his own, but I want more information. Always. I want an actual possession statistic. Not because I don't think Corsi gives us some information on that(it obviously does), but because I'd love to see where they diverge, and then I want to know why they diverge. What types of things show up with individuals, with teams, game to game, long-term...
Cause and effect isn't enough. I want to know why. If there are anomalies, why are they there? Is it something you can reproduce? And if it is, what does that tell you? It's the statistical version of taking apart a phone so I can see how it works. I love that ****.