I agree that "just don't use it" is an invalid argument against game balance...
However, what I -do- find to be a valid argument is, -don't power level Smithing / Enchanting / -. I've never once power leveled Smithing, and never once has it overpowered me. I use it naturally when I want a new weapon, or piece of armor, or if I find something that I want to improve. I never just grind out iron daggers to reach top level and have a full suit of improved Daedric Armor by level 10.
About every other thread gets side tracked int this balance/imbalance thing. And powerleveling/grinding Smithing is always at the top. It has nothing to do with how fast one gets to 100. If someone is set on leveling the skill, they are going to do it no matter if it's with daggers or whatever. Even then it's not that powerful of an issue.
You can't get to 100 Smithing without leveling your car. Even if you try as soon as possible. In fact it is very hard, if not impossible to get Smithing to 100 before level 19 or 20. You have to buy the ingots, kill and explore to get coin to even buy the ingots. Those things will also contribute to your over all level.
Even then, it's not that powerful of an issue. With the perk and 100 Smithing. You are only going to raise your base damage by 10, that is with ANY weapon, Daedric or Iron. Granted that gets multiplied by your selected weapon skill and the perk selections of that skill.
This overpowered thing comes into play when you compound 100 Smith and Perk, PLUS a powerful Fort Smith potion plus gear with powerful Fort Smith enchantments. Which by the way comes from a high level Alchemy and Enchanting skill, which in turn levels your character. This actually puts you closer to level 30 by the time you can improve the super-uber-duber stuff.
So I don't see powerleveling having any bearing on it what so ever. Getting an early jump on the level scaling will eventually catch up with you. Sooner or later.