A review on the name of the planet (EW spoilers)

[Enkidoh]

It makes a kind of sense though for two reasons - Etheirys, as in, the original Ancient world, no longer exists and hasn't existed for 12000 years. It was Sundered into the Source and it's thirteen Shards. Additionally, as a result of the Sundering, everyone's memories were at the very least muddled, if not erased, so the very knowledge of the original name would have quickly disappeared anyway, with successive Calamities all but finishing the job. And as Hydaelyn became "the will of the Star", the planet's consciousness if you will, it makes sense her contact with the planet's inhabitants would result in her name becoming adopted as the world's name.

Really, I found the sudden shift to important npcs using the term 'Etheirys' for the world when they've been calling it 'Hydaelyn' all their lives to be rather jarring, but that was just me. Either way, Yoshi himself basically said "call it what you feel comfortable with, as all the names are really true", and because I'm stubborn, I'm going to keep calling the planet Hydaelyn, except in context of the Ancient world, when Etheirys is appropriate. But that's just me.

[MikkoAkure]

And as Hydaelyn became "the will of the Star", the planet's consciousness if you will, it makes sense her contact with the planet's inhabitants would result in her name becoming adopted as the world's name.

At least to me I thought it was the other way around where the people of our current world referred to the planet as "Hydaelyn" and those very few who found out about the Mothercrystal referred to Her with the same name since She was then the Will of the Star and may as well represent it as a whole. The EE mentions that the first documented Echo bearers described receiving visions from the planet itself and they were implementing "Hydaelyn's Will". I don't think enough people ever existed at one time who knew the "goddess" Hydaelyn existed to be able to influence worldwide society regarding the name of the planet.

We are Her "children" because we are children of the planet, is how I always took it at least. And She and the planet were viewed as the same entity with Her being named after the planet and Her existence is still unknown to the general public.

It would be nice to ask the devs sometime about this chicken and egg scenario though.

As far as the Sharlayans calling it Etheirys all of the sudden, I think they're just the types who, after finding out new info/terminology, feel that they should immediately adapt to it and use it in their everyday.

[Cleretic]

It makes a kind of sense though for two reasons - Etheirys, as in, the original Ancient world, no longer exists and hasn't existed for 12000 years. It was Sundered into the Source and it's thirteen Shards. Additionally, as a result of the Sundering, everyone's memories were at the very least muddled, if not erased, so the very knowledge of the original name would have quickly disappeared anyway, with successive Calamities all but finishing the job. And as Hydaelyn became "the will of the Star", the planet's consciousness if you will, it makes sense her contact with the planet's inhabitants would result in her name becoming adopted as the world's name.

Really, I found the sudden shift to important npcs using the term 'Etheirys' for the world when they've been calling it 'Hydaelyn' all their lives to be rather jarring, but that was just me. Either way, Yoshi himself basically said "call it what you feel comfortable with, as all the names are really true", and because I'm stubborn, I'm going to keep calling the planet Hydaelyn, except in context of the Ancient world, when Etheirys is appropriate. But that's just me.

Yeah, I think the mistake the OP made was presuming that the rename was intentional. There's no reason for that but ego, and Venat was not so egotistical. The name 'Hydaelyn' just caught on as the name of the planet because people kept awakening to the Echo, hearing the voice of someone named Hydaelyn, and going 'oh, that must be the planet'.

I personally disagree with everyone suddenly calling the planet Etheirys, but it was probably a benefit to clarity that they did for the expansion when both the planet and the god were both major factors. As to an in-universe reason, though... honestly, I'm gonna attribute it to the fact that everyone who does that is from Sharlayan, and Sharlayan as a nation is so nerdy and full of themselves that they'd absolutely lord a new way to be right over people. Basically, all of them are preparing for a chance to pull the 'actually, Frankenstein was the doctor's name' card.