I’d love to have the discussion some time about how close two similar specs need to be before players will play the one that is most fun for them and not the one that does theoretical higher damage. Is it 5%? 1%? 0%?
In case you're interested in the answer: It is -1%. Oh, you think -1% is impossible? You're correct. See, the players don't play a specc because it is 1% more effective. They play it because they follow their peers, and because it is so simple to respecc.
Ironically, Ghostcrawler just learns the same lesson, the designers of skill-based games have learned before: If there is no friction, there's no way to keep the marbles from moving towards the lowest point. And if there is no lowest point, the players fake-invent one!
On the other hand, if there is friction, the problem becomes a no brainer. This is from Daxxarri, community manager of WoW:
Overall, we've never seen a strong correlation between which class is considered overpowered and what players are playing.
See? Add some friction and the problem is solved. It's not a balance problem, dear Ghostercrawler.
In fact, even if players play overpowered classes more, it's not automatically a problem! Did you read Eric at Elder Game, Lead Engineer and Producer of Asherons Call 2?
Turns out that the people who played the other classes available to that race had taken on an “underdog” mentality. The people who played Claw Bearers liked that they were woefully underpowered compared to Feral Intendants. It was like playing the game on Hard Mode. And the people playing Feral Intendants liked playing on Easy Mode. In balancing the game I had failed to understand the needs of the people playing it.
Unless they become really grave, balance-problems aren't fun-problems. A MMORPG can be absolutely fun even though it is unbalanced. And that's especially true if there is some friction that hasn't been removed yet in the name of convenience, metrics and "less punishing gameplay".
Not turning MMORPGs into super-challenging sports that requires perfect optimization helps, too.
Thanks to Raph Koster's blog I found this gem: "Don't play games with me". Start at slide 46, if you are short on time. Added it to the really good links.