@jon-mitchell
There is not much divergence between the anime and the LN, in my opinion, though of course there are moments that are greatly expanded, but this should be expected.
The novel is complete, 10 full volumes and 3 side stories. The series does not end up in the air, however the best way to describe it is "rushed" and it leaves the reader feeling unsatisfied i.e. half full. However, I would only describe that truly as the last volume.
Are there loose ends? Yes.
Are they significant and would prevent the story making sense? No.
Is it still worth a read? Absolutely, but it would never be top of the list.
Just my two pence on the matter.