The only nerf I expect from Eureka is when 5.0 comes out, and at that point they should just drop the loss of exp/level penalty, at least as long as you were at the same level of the monster or higher. Right now this penalty is the only reason why not to single-player the entire thing. A tank, healer or RDM can more or less endure this content with chains, but it's slow. Other DPS, do not have adequate time to recover HP to do a chain.
Like, I get why this content exists, it's basically the same insane grind of the 2.x and 3.x relic weapons. What did they nerf for those? They removed quantities, not steps. Light grind was never actually "nerfed" per se in HW relic weapons, they just made all the dungeons give the same amount of light, thus brayflox HM wound up being the fastest thing to solo to do due to the lack of obstacles. I imagine a similar thing exists for Pagos, just players who leeched off the Anemos train are now complaining about it.
Footnote: When digging up videos from 2013, we had FATE trains back then too on the regular ARR maps. You might ask, "gee why would anyone level off FATE"'s and well wouldn't you know it, ARR didn't give out as much experience back then, and DPS were essentially locked out of dungeon queues due to there being too many of them and not enough healers and tanks. While a "train" mechanic isn't inherently bad, it's borderline cheating since it's not the intended mechanism to level up, and by doing so, it exposed a weakness in the lockboxes rng, since you didn't get anywhere near as many boxes if you played it the way it was intended.
So it seems they "fixed" that for Pagos, but in all honestly I consider the Eureka content to just be a "bad" design where we wouldn't have complained so loudly about it had the content had a halflife of at least one patch cycle, but instead the train reduced the halflife to one day, and everyone else went back to doing what they were doing before, and complaining they are bored.
I'll say it again, some of you people are only bored because you choose to making it boring. If SE was in it's right mind behind some design decisions, they'd realize that they should offer the best reward something for clearing content synced on minimum ilevel, and never for unsynced. All parties should be levelsynced/ilevelsynced to the value of the weakest member of the party, and the Eureka content is one of those places where this was a glaring oversight, but not the only content where it creates that problem. All content should be levelsynced to the weakest player when a party is formed, that would allow high-level players to be able to party with low-level ones, anywhere.