>>123986971. There are a lot of dark areas bellow so mobs can spawn there.
2. Spiders can still climb the inner wall, un-slayed, & will lower the spawn rate over time (TTT has the same problem)
Solution:
Since Ame doesn't want to nuke it all, then she needs to drill a hole all the way to the bedrock & light it up.
Without the bottom spawn problem, it will be better than TTT since it will also farm spiders for strings that can be turned into tripwires, something that the JP server doesn't have.
The trapdoors are actually good & encourage the mobs to spawn near the bottom.