I've said it a few times, smithing is a mechanic for people who beyond a shadow of a doubt detest themselves and decide that they require the most creative, painful and barbaric of punishments.
This, of course, is only hyperbole. But by how much is for the individual to decide.
The stamina limit is too low.
The regen is too low.
The amount of stuff you need to do, even with a 100% success rate to get a new part, is too much.
Getting parts you want is practically impossible, or rather improbable.
The system itself is awesome, put together parts for a weapon! I really love that! But what if you want a specific look? Well... that's what you'd be smithing for more than likely. Now, good luck with that. You can't aim for any specific part and have to by sheer luck get it. You get polearm parts for tearing apart swords. It'd make sense if taking apart a sabre gave you sabre parts! But nope.
At 300 smithing your maximum stamina is 100. You can barely do anything with this.
But hey in some cases you can buy weapons, take them apart for parts and sell parts on the same market for more. So that's nice? Just doesn't make any sense.