The spam checker's gibberish detection is tied to the overall spam sensitivity setting. Admins who want to tighten gibberish detection without changing the broader spam threshold have no way to do this independently.
Admins should be able to configure the gibberish detection threshold in the spam checker as a separate control, independent of the overall spam sensitivity level.
Gibberish submissions and spam submissions are different problems that warrant different sensitivities. Conflating them into one setting forces admins to choose between over-blocking real submissions or under-blocking gibberish.