Who's talking about easy to get powerful artifacts, we're talking about well-hidden, well protected, cleverly placed artifacts that makes the experience feel rewarding.
Then I agree, but we'd need to nerf invisibility and telekinesis. And unlike some people said here, no the morrowind system didn't work. Rare and powerful items weren't even protected by very strong monsters like dremoras or golden saints, on lvl 1-2 there were only ancestral ghosts that were very easily beaten.
Combat items only make enchantments useless if you can't find any decent weapons (due to BS Scaled Leveling System) and/or lack any imagination whatsoever in creating enchantments.
Tell me if any enchantment you did could beat Marara's ring or if a dwemer jinkblade that paralyzes for 10 secs and just costs 450 is fair...
Anyway, if the artifacts were balanced and were actually hard to get I agree they should exist, unlike the Morrowind's system.
And a better item makes lesser items useless, what it your point? This is why they are hard to get.
I wouldn't call Azura's star hard to get (neither on Morrowind or Oblivion)... It would be more challenging if for any soul you needed to get you'd have to buy a grand soulgem.