7. Not sure what DPL is specifically, so my opinion is not fully informed, but I disagree. If you're a (new) reader and look up a character in the wiki, it's your own fault if you get spoiled. Hiding the status in the character sheet is already a precaution, but looking at which category a character has or - god forbid - the category itself kind of makes it your own fault.
8. I'd rather have it either in Category:Earthers or in both.
15. Disagree, it belongs in either Category:Artifacts or both.
19. Why are these even a thing? Genuinely curious. I agree with SerBear's opinion on this.
23. Not sure why it would be a city-state specifically? Walled Cities can only influence it to a certain degree, but to me this doesn't make Liscor a state per se. If having autonomy from Walled Cities made it a state, there'd be many more city states, than just the ones that are currently categorized.
28. Either have Category:Mounts be a subcategory of Category:Vehicles or have both of them be a subcategory for something like "Transport" or "Personal Transport"
All others I tend to agree with or wouldn't mind either way.