I've now run the second wing of Nighthold in LFR, or at least part of it. Unfortunately I got in having read up on the wrong fights - of the three I read up on, the two that were still up when I got there were both ones I did not realize I'd be facing. So let's make this clear:
Royal Atheneum is Spellblade Auriel, Star Augur Etraeus, and High Botanist Tel'arn.
I'm not going to go into my usual guide mode, as I'm still kind of processing the fights (when I run it on other characters, I'll try to get that out there.)
This has the players emerge out from the sewers and take the fight to Elisande's main forces. I suspect that Etraeus and possibly Tel'arn are both optional fights when you do this on Normal or above. Notably, Star Augur Etraeus has the tier 19 gloves (something I got the LFR version of, which are 860 item level.)
While certainly not as mind-bending visually than the Emerald Nightmare, Nighthold really seems to be a continuation of the Suramar aesthetic, something that I think they've really pulled off well this expansion. In fact, when the raid was announced, I was pretty disappointed that the Emerald Nightmare wasn't even going to be the headliner of its own raid tier, but while I still think they could have done that (I'm glad there will be three raid tiers after Warlords' disappointing two, but I honestly think they could have held Emerald Nightmare back as tier 20 and then done Tomb of Sargeras as 21 and Argus as 22, matching Wrath with four raid tiers) I'm actually finding myself way more invested in the Nightfallen/Suramar storyline than I expected myself to be.
We're also in a pretty interesting position gear-wise, given that Nighthold LFR is now giving gear that's on par (or even exceeding, I think) Return to Karazhan gear and Emerald Nightmare Normal. I still haven't gotten very far in RtK (I think we may have gotten Attumen down once...?) but I'm hoping we can get a little farther before the far easier, queueable heroic modes come out.
I have to wonder what the plan is for mythic dungeons. Yes, I realize mythic plus allows them to scale sort of indefinitely, but I'd rather that mythic plus worked more like standard difficulties - without time limits so that if someone has to go to the bathroom or something they aren't penalizing the team. The point is that at this point, with LFR giving gear that's 15-20 item levels higher than mythic dungeons, dungeons are in danger of falling back into Mists/Warlords-era irrelevance.