So I'm a certified Lore geek so much so I love collecting all the information I can. But there's somethings in the game I do not understand what happened to and if we're ever going to get answers on.
1.Arlon Bladeshaper... The mysterious head of the Nashers who was talking about working with his other "allies" and that the crown should be on his head. Was the Cloaked Ascendancy his other allies? Did he get betrayed or disappeared into the ether? Just wondering what happened to him.
2. Vizeran Devir and the Elemental Eye. We see him and Vanifer talking at the end of Maze Engine and not a peep from them since. I'm guessing that's still planned for a future update?
3.What happened to the Soulmonger and the death curse? There was no epilogue for Chult. Like there's a big discussion about whether or not to destroy the Soulmonger and we did I guess in killing that giant baby but it's been brought up in Sharandar by certain factions as well as Valindra's name. Did she take what's left? And how is Thay and her tied into keeping the Feywild portal shut?
4.And finally what's going on with Makos now that he's helped us in Avernus and he's learned secrets about breaking pacts with devil's and demons?
2 - Was probably interested to be continued but we've had near total turnover in the dev team. In the tabletop sourcebook, Vizeran is the one who is responsible for the prophets unique weapons in Elemental Evil but he only appears as an ally of the players in Underdark, of which Maze Engine was a side story. Any continuation of the story in NW would be/have been fully written by Cryptic. Note that the foreshadowing with Makos did get followed up on.
3 - The Soulmonger artifact is the big cylinder that he Death Babby gets pulled down onto and crushed. While additional dialog from NPCs would have been nice, the Death Curse was ended with the destruction of the artifact, death of the Atropal and driving off Acerack. The lich could well come back for revenge but that would be a new story.
4 - That was only the previous storyline, 21 not having one so it hasn't really been that long.
My plot holes would include:
a real resolution with the Dread Ring... the fight with Valindra doesn't mean anything to her plans... she just gets a new body and resumes her plans.
Who was the Masked Stranger in Brynn Shander working for... Storvald? Serissa's Sisters...? It seems obvious the plan was to stir up the Reghed against the city, but to what end.
How did the giants find Storvald? The ring protects its owner from magical detection and the tabletop book expressly states Storvald has no real chance to find him.
What is the significance of the witch and farmhouse in Lonelywood? Just random chance, teaser for a Barovia that got delayed?
What ARE those fools doing in Daledrop Vale and what did the other fools do with the phylactery?
Heck, for all we know the next major event deals with Dragons and the aftermath of the Rage of Dragons curse/mythal being broken over a century ago. This curse by the elves caused all dragons to being extra violent and overextended, often leading to their deaths due to humanoids, thus keeping their numbers culled. We will know for sure by next year ofc. 2. I think even though Maze Engine was introduced after Elemental Evil, the events of ME took place before EE
3. Not sure about the details of the soulmonger, but Valindra did attack Sharandar during her war with Neverwinter through Malabolg. The Red Wizards could just be those that remained in touch with the dark fey. Although I would love to see Valindra return to the story with a vengeance.
4. I'm sure Makos will turn up sooner or later, I'm sure he doesn't want to return to Neverwinter and face Celeste just yet.
Best answer, there are and will be no answers. The writers and developers of the content, mentioned for this game, are sacked or left for higher ground. If you look for answers within the game, you will be waiting forever.
My wife was upset they seldom or never concluded any of their plots in this game. She has told me before that most leave the player hanging off the cliff. The few endings she showed me are like the party at the end of The Dwaven King or the final chapter in Cloaked Ascendancy. Otherwise you are expected to make up your own ending.
While I only use this game to debug Wine for Linux, I can add to your list of plot holes.
Did anyone tell Xuna about Makos? They seemed to have a good relationship in SKT but then stuff happened. What you have to remember about Xuna's limited backstory, she hates the undead with a great passion. An undead killed her father, the one she kills in the battle of Neverwinter in the opening cut scene. Instead these main characters were dropped.
Another issue with lore in any online video game is the database. All databases have limitations, the vast majority of players will skip dialog and developers know this for a fact. If they have a question about the quest, they can look it up in their log or journal. This is just another reason, when I play D&D it is done at the kitchen table. People are damn lucky I am not a developer with a lot of pull. My rule would be, any player skipping dialog would get to wear a title "Mister Know-it-all" and they would never be offered any instructions or help by the game ever again.
Just take a look at this poor sap in this short video.
PSN Zen AD Exchange - Forecasting Spreadsheet