At this point, we're basically chasing down the Gúrzyul, the former disciples of Sauron. This mainly includes Dulgabêth, the Mouth of Sauron; Karazgar the Weeping Warrior; and Urudanî Stonemaiden, previously the mistress of Nargroth and currently a fire-wraith. Karazgar is involved most of the Black Book story in the Three Kingdoms (Felegroth, Dale, and Erebor) and The Dwarf-Holds (Iron Hills and Ered Mithrin). He also appears in the Vales of the Anduin. His story is never adequately completed, before you are whisked away to help Isildur (himself now a wraith) find a final peace in the final chapters of the Black Book.
The other ongoing antagonist is Lhaereth the Stained, the Lady of Blight, a Morroval who is adept at brewing up plagues and poisons.
The new area, Wells of Langflood, has started a whole new epic line. In it, players are headed to Gundabad with the dwarfs - Prince Durin (Son of King Thorin III) has decreed that the dwarfs are destined to reclaim it. This area is relatively easy and has no real endgame - there's an ongoing series of quests to defeat some named goblins in various instances. The epic doesn't really go anywhere, and the main non-epic story involves a Rohirric scholar trying to suss out the history of the people.
End-game instances are still related to Minas Morgul. There is a series of rep tiers - the reclamation quests - that require you to run them endlessly until you max out your rep with this faction. As you unlock each tier, you unlock an associated quest chain that involves destroying a particular artifact so that you can defeat some random baddie named Thargaun.
The state of gear is still bad. The best landscape gear is still obtained from lootboxes, and it's still all about essences. Crafting is still a waste of time.
The new virtue system is just another grind, unless you're willing to buy stuff from the store.
If you've not played since HD, you have a lot of catching up to do. If you intend to imbue your LIs at lvl 100, you'll be grinding scrolls of empowerment for months (unless you're willing to spend MC), as there is no good solution even now. You'll also need starlit crystals for the main LI stat, and the crystals are even rarer (and I've found it's easier just to MC the tiers - it only costs 10 MCs per tier). They have added both the scrolls and crystals to the embers NPC now.
Overall, I feel that the game has become repetitive - it's always kill 10 of these, pick up 10 of that, grind the rep for this faction, and spend the tokens for some cosmetics, housing items, or cosmetic pets.
One note: the Minas Morgul currency is account-wide, and capped at 999 sigils. This is perhaps the stupidest idea ever, especially if you intend to take multiple characters through the region. There is very little to spend the sigils on, and so you end up losing them.