My thoughts, based on a very quick initial glance through the preview on Amazon:
- I wouldn’t worry too much about the page count, there. That seems reasonable, especially because even in the preview, there were a few image-only pages, so that part should be fine.
- Vocabulary is a problem that the vocabulary sheets generally solve, so I wouldn’t stress about this part too much either.
- While there were depictions of violence and some blood, nothing struck me as particularly gory or over the top in the preview that I could see, so I would tentatively say that’s relatively safe as well (maybe in your nomination post, you can post some examples of that behind spoilers/trigger warnings and people can look and judge for themselves if it is something they would consider too explicit. It’s not something that bothers me too much, personally, so my opinion should be taken very lightly into this consideration).
- The part that would maybe give me some concern: Do you know if the entire manga has the same amount of text throughout? From the formatting and what I was skimming over, it would appear that the pages with heavier amounts of text are primarily exposition, so presumably introducing characters, so if the text kinda eases off after the first little bit, it wouldn’t be an issue, but if that’s the amount of text throughout, I might be a little more inclined to bump it up to the BBC, purely because it’s harder for newer readers to get through the amount of text that would be present.
Overall, I would say there is no harm in nominating it. Just be sure to include representative samples of pages so that people know what to expect, and the difficulty poll could serve as the final decision maker for us. If too many people vote on the highest ends of the difficulty poll, you can just move it to the BBC instead!
Edit: Also, I checked out of curiosity, and the Natively rating is currently a tentative L30, but it doesn’t look like it has really been graded, and that’s just a guess, as opposed to based on any actual ratings from those who have read it. If it really does fall into the L30 range, then it should be bumped up for sure, but since we don’t have any actual gradings, I would hate deny it on that basis alone.