Artifacts originally had special typings (Mono, Poly, and Continuous) which would mostly be rendered moot by the invention of a tap symbol
Having Hexproof is nice and makes you feel safe, but I ran Aegis of the Gods in Azor for years and it almost never saved me from anything, not only because having hexproof isn't as strong as it seems but also because people will want to kill it very quickly if they do need to target you
It is also nice for Wizards to have a product that they can put in mechanically unique cards into, as you cant do this with regular sets
For the same amount of mana they now get a commander that rewards the decks go-wide artifact strategy and its unearth subtheme, at a terrifyingly efficient rate
Taking out something isnt a negative commentary on what leaves
Until new precons and legendary creatures are announced and released the true long-term demand will remain a mystery