Before I begin, please note that I am in no way saying anything negative about the people mentioned in this post. It is just an opinion, and speculation on my part.
As of late, I have noticed that Christopher Tolkien is editing less Tolkien material, and that Veryln Flieger has been editing more.
Is it entirely possible that Christopher Tolkien is either stepping away, reducing his duties or handing the reigns to someone else? Any, or all three, are possible. However, please note that this post is purely guesswork and opinion.
Christopher Tolkien has been editing Tolkien material since the 1970s (and assisting his father beforehand, as well) with projects such as The Silmarillion, Unfinished Tales, and The History of Middle-earth. He edited other Tolkien books here and there, but continued to do so from 2007 - 2014, with publications such as The Children of Hurin, The Legend of Sigurd and Gudrun, The Fall of Arthur and Beowulf. This year he turns 92.
You may have noticed that I didn't mention The Story of Kullervo. For that publication, Veryln Flieger took the role of editor. This year will also see The Lay of Aortrou and Itroun re-published. Verlyn once again takes on the editing role, while Christopher Tolkien will supply a new prefatory note on the text.
As I mentioned, the fact that Christopher hasn't edited a Tolkien book since Beowulf is purely guesswork. He didn't after all, work on The History of The Hobbit, either. Maybe he's taking it slow and steady these days, with reduced roles and responsibilities. Maybe he's hard at work on something else.
I confess I do not know that much, or anything, bout how Tolkien projects get handled. I have noticed that usually Christopher Tolkien takes on the big or significant projects. Not to undermine their work, other Tolkien scholars and experts also pour huge amount of work and dedication into their work as well. They usually work on supplementary work, study or analysis which examine or enhance Tolkien's works.
First up of additional mention, is Wayne G. Hammond and Christina Scull. If I don't know the answer to something Tolkien related, I usually point the asker towards works by them. Their Lord of the the Rings Reader's Companion is sometimes contained in the same box set as The Lord of the Rings. Not only that, but they were heavily involved with the updating and correcting for The Lord of the Rings' 50th (and up) publications. Those two facts alone right there show me they know their stuff.
Then, there's the Tolkien Reader's Guide and Chronology. It's being revised and re-published next fall. This multi-volume set presents anything and everything you could possibly wish to know about Tolkien. On top of that, they have also done other projects, such as those about Tolkien's artwork (Artist & Illustrator, The Art of the Hobbit, and The Art of the Lord of the Rings)
There's also Douglas A. Anderson, also involved in Tolkien's texts. He is among other scholars, such as Verlyn, involved with Tolkien Studies. Most famously, he is responsible for The Annotated Hobbit.
There is also John D. Rateliff, who received Christopher Tolkien's blessing for The History of the Hobbit, which is a sort of companion to The History of Middle-earth.
There are many others that deserve mention as well: Brian Sibley, Tom Shippey, Alan Bliss, Karen Wynn Fonstad, John Garth, Humphrey Carpenter, Dimitra Fimi, Andrew Higgins, and many more.
It is good to see that Tolkien's legacy is in good, responsible and respectful hands. As ever, I look forward to what come next; whether it'll be a brand new publication, revised and and updated re-issues of current works, anniversary editions of existing books.
I am definitely grateful to all of them, and appreciate their hard work and dedication. Once I even gave some information about my Lord of the Rings boxed set to Hammond + Scull's blog, which I hope has been of assistance to them.
As always, keep an eye on my blog, and once I'm aware of upcoming Tolkien books of note, I'll be sure to spread the word by doing a post.