You can technically see if your Fraxure has low initial stats, or anything that's rather sub-par. Go to the Battle Subway and talk to the Ace Trainer you see near immediately at the entrance. If Fraxure is as bad as you think it is, he'll probably say something like it being so-so or decent.
Also, it gets phenomenally powerful once it reaches Haxorus, so it might just be seeming to be weak because right now it's just a mere Fraxure. Training my Zweilous was a little difficult because it wasn't very outstanding and got hurt a lot fighting Pokémon around or higher of its level range. Once it evolved to a Hydreigon though, I was able to have a much easier time wiping enemies out.
Leveling up a Pokémon from 1 up doesn't necessarily mean that you'll get a better Axew or anything. It's all random again, and it's luck to you on whether certain marvelous initial stats of the parents get passed down to the offspring. There's ways to influence it though with certain items, but it's all up to the parents' own stats once more.
Finally, as hiff said, it might just be a hindering nature. You can look at the link he provided to see all the natures, but if you want to see what particular stat is growing or hindered, you can actually check your Fraxure's status screen. The stat with a subtle highlight in red is the helping one while the one stat highlighted in blue is the hindered stat.
Minerals? Vitamins, you mean? Proteins and Carbos can help, but it only goes so much, you know.
I feel like you were expecting an amazing Pokémon, but right now you're a little disappointed that it doesn't seem as marvelous as the hype was. But as I said again, perhaps evolving it to Haxorus will show you the awesomeness that this dragon holds.
By the way, Dragon Dance is an awesome thing for Fraxure. It helped me train the fellow quite quickly.