As suggested by Blizzard’s support itself (GM Hasagozata), I’m here to submit this issue as a bug.
I really don’t understand why Blizzzard decided going with 540 and not 750 for ethernal mythic uniques. I mean, it’s an abstract number anyways and it has no impact in seasonal content or expansion characters. This would obliously still be underpowered for items that Blizzard chose to advertise as “the best in the game”, but at least they would be usable for eternal chars with possibly hundred of hours of gameplay.
I understand this might be against Blizzard policy, but this is a refundable type of problematic decision. And some of those gears were gathered in season 5, not like when everything was being tested and devs were tweaking tons of bugs in the game.
Why completely remove eternal players from the game? I at lease deserve a serious answer to this question.
PS: I’m not a streamer who plays this game 10 hours a day. I usually get to achieve something meaningful (at least to me) at the end of seasons. So this is literally removing something I have very little chance of achieving otherwise.