Since I came back to the game, I decided I'd do some stats stuff with the ladder and Blizzard's API. The formatting is terrible, but still, the information is interesting. If anyone wants to clean up the formatting, I'll gladly edit the OP and give you credit.
The following are some statistics parsed from the US 3v3 leaderboard. I also coined something called "OP Rating" (a misnomer for sure, but still an interesting way to look at things). This rating is just the ratio of overall spec representation vs representation above a certain rating. As an example, I don't think it's enough to say, "Wow, Resto Shaman make up 11.4% of the population above 2400! They're clearly broken!" They may or may not be, but if they were 20% of the total ladder population, then one could argue they are under-represented above 2400, or conversely if they were 5% of the total ladder population, then that would suggest they are over-represented above 2400. The "OP Rating" at the end of the output is exactly that ratio: total spec representation vs spec representation above a certain rating. (Prot paladins probably are as ridiculous as people think).
In an ideal world, perhaps every spec's "OP rating" would be close to 1. Meaning that they are found in the same distribution at low ratings and at higher ratings. To explain this more, Havoc Demon Hunters make up 2.02% of the entire ladder consumable by the API, yet they only have 0.69% representation over 2200 and so their "OP rating" at 2200 is 0.34 (well below 1).
I'm not personally interested in debating class balance things, just kinda presenting some raw info for people to look at and mull over. It's interesting if nothing else.