For myself, I think Tolkien's long poetic versions were to be part of Bilbo's three volume
Translations from the Elvish, or at least
The Children of Hurin and
Beren and Luthien poems, two different kinds of poetry.
And, well, lots of other stuff
Also, I think (and if I recall correctly, this might echo Christopher Tolkien's opinion) that the Annals were merging in style and relative fullness with QS, and so a new
Tale of Years, including the First Age, was going to step in there.