Lets be honest here. None side will ever convince the other side, about Eureka. Eureka will become the most controversial Content of the Game.
The one side loves it and the other site hates it and both do this from the bottom of their Hearts.
And in all those Years, I have never seen something like this in any Game. Not at this scale. There were always topic and content people did not like.
But this is really a "love" and "hate" thing.

My Opinion here. It was just to much of it.
There will never be content, that everybody likes, but Eureka was just to much of the same thing. 4 Times and it dominated the whole Update of the Game.
The Palace of the Dead and HoH were never super popular, but they appeared once per Addon, and people can look over something like that.
But Eureka came 4 times and from my guess, this will repeat with the Addon and they will add something like Eureka to every x.1 Content Patch.

The Diadem was a failure and this is because of Fates and the wrong usage of Data by the Devs. They attach every Event to Fates, the Yokai Event was a Fate hell and after that, they look at the Data and say "Oh, they do Fates, Fates must be popular.".
But the people did them, because there was no other way to play the Event.
The Devs do not or don't want to understand, that Fates are not the most beloved things of this Game. A lot of people do not like Fates. Often the reason is the Combat System.
It is a slow Combat System, with long GCDs and long Cooldowns for Skills. And that can be fun, when you fight Bosses with Mechanics and your Rotation starts to work. But when a fight is just around 15 Seconds or a mess of Parties like Fates. The Combat System is not fun.
It feels like someone took Titanfall and made a coverbased Shooter out of it and kept the Parcour Movement System in the Game. A does not work well with B.
And I do not like, how the Devs again talk about Combat Reworks, like they try to change the Combat to work well with Eurekas Trasmob farming.

One of the major Problems of the Game is the large lack of Midcore Content. There is not much to do for a lot of people who want such a type of Content.
The only thing, I would call Midcore Content in this Game are the Ex Primals. But this is one fight for 6 Months.
Maybe you can add Savage 1&2 to that, but they come with the ID System, so you can't really play them for fun, when you have the weekly clear...or everybody will just hate you.

Eureka is Content for a Casual Skilllevel, but that does not make it better it even makes in more stale, because a lot of players feel so unchallenged by that Place.
It is just a large Skinner Box, that conditions the Player to slay Trashmobs and Fatemonsters over and over again. With Random Rewards.
And they attached a lot of things to it, that feel important to the majority of Players.

To be honest here. From my View, Eureka is cheap and lazy Game Design, with a lack of thought put into it how it really could be fun and enjoyable as a Content. They slapped a Ton of rare Rewards into it and called it a day.
A commonly used Phrase to defend it is "It is fun with Friends.". Even bad Games like DayZ Standalone can be fun with friends. Mostly, because the people enjoy time with their Friends. Even a Gulag becomes less worse, when you had some Friends there.

For the Question: Would people play Savage if there would be no Gear Rewards?
Isn't is really sad, that the answer for a lot of people would be no.
Isn't that just super sad?
The knowledge, that a lot of people would not want to play some Content, because there is no Carrot on a Stick inside of it.