I actually think the Aetherpact kinda fits with the way they changed Arcanist.
Originally it was even wierder prior to Stormblood, back then it was actually more of an EQ Necromancer combined with Summoner (the Carbunkle/Egis). There you had 5 DoTs, 2 Bios and 3 Miasmas that all stacked, you had Bane which spread them out in an AoE, then you would use Garuda's "contagion" ability to extend the timers by 10 seconds.
It was always Ruin-based. Because your Ruin increased in potency by the number of DoTs stacked on the target. It took a while to spin it up, but once all the DoTs were stacked and you were spamming Ruin it was actually really good DPS.
They were removing that throughout Stormblood and SHB. What you saw in Stormblood and SHB were just the last vestiges of that. And only a small portion.
In Endwalker they totally removed that function other than very small names like Fester and Painflare. Aetherpact was not originally attached to the Dreadwyrm Trance. That was a Stormblood addition.
We knew they were slowly removing the Necromancer part of the Arcanist over time. We just didn't see the full results until now.
Problem being... those Necromancer abilities and Pet abilities were a LARGE portion of Gameplay for the Class as a whole.
It is OK to link Aetherpact to the Carbuncle summons... the problem is making up for all that extra gameplay that used to be a part of the class. You went from a full rotation of 5 DoTs + Pet Actions + Ruin Spam to just... Ruin Spam with only an occasional Aetherpact every 30 seconds or so for 3 former Pet Enkindles. That is why it is so plain and boring and just... one button spam.
It was ok to do the Aetherpact thing... BUT... they still need to make it more than just Ruin Spam on the Aetherpact Summons.
Hence why I suggested Carbuncle/Egi powers for the Deathflare/Enkindle buttons during the Carby Summons so its not just Ruin Spam, Ruin Spam, Ruin Spam. That's why I said the criticisms are actually right at early levels now.