And if the pope had tested it, it wouldn't mean much.
You're right, it wouldn't - good thing that people who have a background in game development are testing it. Also like to not, that a good part of Splash Damage started out as gamers modding for Quake 3 - they aren't simply people who went to school to make games - they have a beter understanding of what works and what doesn't because 1) they have already made 2 games that follow this type of gameplay and 2) they understand aspects in game from both a developer and players point of view. They also have test the game themselves and have testers that test it as well, not to mention the extra 7 months between announcing the game getting pushed to 2011, and the new release date, that they have spent tweaking and polishing the game.
For a fact, game-developers get things wrong just as often as they get things right. A large community testing stuff would rather get it right than a small team of people.
But in this case, your opinion is kind of moot. They changed a feature because it was too powerful. If a game is played for months (if not longer) and the majority of a small group of testers/players decide something is overpowered, chances are, that's because it is. What makes you think testing it in a larger community would change this? If a small group of players can see something is OP, why wouldn't the general public? And even if players didn't view it as overpowered, the majority of the public decide on features based on what they like or what best serves them, rather then actually focusing on game balance as a whole. And if it was that much of a problem, it would most likely be fixed in a patch regardless.
In this circumstance, it's better releasing the game having a skill perhaps not being powerful enough rather than having it be too powerful, so even if they're wrong, it's still the "safer" solution.