Not sure how I feel about this—even after looking over her data...is נָא really a particle of politeness?
Dallaire looks at the Ugaritic and Hebrew data and concludes it is—which is a return to the position that was held pre-Ugaritic. Once the Ugaritic tablets were deciphered, scholar's noted n' was frequently used with the imperative. It became common to refer to it as the imperative marker. After all, in unpointed (without vowels) texts, there needs to be a way to mark the imperative when context isn't enough.
Now Dallaire has reexamined the data and returned to the old conclusion...As I said, I'm not totally convinced. But, I haven't studied the data as closely as she has. And I don't have the motivation or time to do it.
To do it properly, one would need to look at every occurrence of an imperative (or potential imperative) in the Ugaritic corpus. And, you would need to make a distinction based on genre—as we all know, poetry does funky things with grammar! And then you would have to do the same with the Biblical Hebrew texts.
Not this kid! But what about some PhD candidate somewhere? Sounds like it could be a good dissertation topic...