... by only ever enchanting an item after you've Improved it at the smithy to whatever level you want?

That trick doesn't help if you want to improve an artifact.

Problem is, if you also picked up Enchanting...there are no items in the game that drop that are superior to what you can make yourself.

Yeah, I did this for a while. But then I realized that if I had weapons improved to fine and then enchanted them, I couldn't further improve them, so I picked up the perk.