if you worry about your adamantine armor being obsolete, just wear a helmet and it already is since the benefit of the minor property "adamantine" is "immunity to critical hits".
I worry about both ...
Either Adamantine gear will look like some lowlevel weak scrap ... wich seems bad to me. :-/
Or we get our hands to incredibly powerfull and stron artefact so early in the game, so any other gear we find will be irellevant ... wich also seems bad. :-/
And the worse idea is that i may in the future Acts find "steel" helmet that will give me even better bonuses. :-/ I mean switching something so rare as Adamantine for something so Common as Steel? Ugh. :-/