Well, I believe you are wrong. For the following reasons:
1. Just because you're better at the game (supposedly), you aren't necessarily smarter or better at balancing. Even a complete noob that uses their brain can understand why champion cavalry are too strong at the moment, no matter if they ever built some themselves.
2. If you're actively playing the game and investing a lot of time into it (which you need to reach a highly skilled level of gameplay), chances are that your opinion on a good balance is biased. Because you want your favourite strategy to be viable (or perhaps even the best), while you want strategies that you struggle against to be reduced in effectiveness, even if they may not actually need any balancing.
3. Concerning yourself only with the opinions of pro players inadvertently leads to a worse experience for less skilled players. This can be seen in almost all teamgames that have an E-sport scene; some tactics only become very good with communication and teamplay, but nerfing the tactic itself will make it unusable in casual play.
Well, either you make fanatics more expensive to reduce their cost-effectiveness or you aren't actually making them more expensive, in which case such a change would be useless. A good player can balance his eco (as you should know if you're playing in "op games"), so it doesnt actually matter to him whether its a metal or food cost.
The only exception being that metal has a ceiling of how many gatherers it can have and a ceiling of how much metal you can mine. Both of which are pretty much irrelevant in early p2.