this idea is its too big of a change, to large and too nuanced with intricate details.
the biggest flaw in it is the fact you want to rework items as well to have - resists on them
your idea wouldnt be “bad” for a new game, but its WAY too big a change to put in D2.
your not so muching “fixing an issue” as u are completly reworking how the game is played… and at that point is just not d2 anymore.
believe me, i hate immunities and i would all for removing immunities, but your idea too complex of a thing to add with breaking stuff or reworking to much stuff… even the best idea i had for it… is still crazy complex and hard to wrap your head around.