We don’t have to ‘replace’ any antagonist, it’s not like we have a cap on antagonists, and even if there were, there’s new slots open now with the removal of monkey/swarmers.
That being said, clock cult wasn’t a very good antagonist, and TG has said they would be willing to re-add it if someone makes it from the ground up, it’s just that no one HAS.
And don’t try to port it from Yog or Bee, because those suffers the same problems as old clockies. Nor should you try to PR it to Fulp, as I doubt it would be able to be made modular in the slightest.