Eureka wasn't a failure per say, it could have been good but they lack any innovation to go outside the box, nobody wants simple level grind and more stats, people want fun exciting mechanics, new interesting stats like they had in 1.0(jump+5%, cure potency+5%) as an example, people want ways to differentiate themselves from others and it not to always seem to linear, like how it keeps being ever since 2.0, it's always grind this, level up, get the same stats over and over with a higher ilvl and nothing to show for the content we've done up until now except glamour which is dumb, equipment should stay relevant for situations over than glamour that way we feel we accomplished something, for example the way they are handling relics currently, they feel weak and outdated every time you finish, cause literally the next patch after you get things that are way easier to get and better immediately. Honestly I prefered the original relic steps, where we feel like we earned it by the end of it and it was relevant for a long time as opposed to how it is now.

If i would have to say what they should do with them, i'd probably say they should make you do multiple different content from low to high, and just make it to where you can take any armor or weapon in game and progress them through levels by doing different content and leveling the equipment yourself. Start all equipment at level 1 and just let people progress the equipment over time depending how you do content and get different stats until you finally get to the max level of the current content and then work on it from there per patch that way it would make everyone feel like they progressed and made their own unique relic weapons and armors that might feel unique to everyone else's cause they chose their own stats, style, and unique buffs on the equipment.