Hey Iswearitwasthere,
No, I'm afraid you're not remembering that quite right. In Wurst 7.45pre1 and pre2, I brought back the TemplateTool hack, made ChatTranslator work in both directions, and fixed various bugs. I didn't make any changes to KillPotion or similar creative mode-only hacks.
Creative-only features like KillPotion are limited by Minecraft's server code. In survival mode, the server restricts certain actions like spawning in items or directly modifying NBT/component data. The client can always request these actions, but if the server doesn't grant them, it won't happen. So these creative mode requirements aren't something that a client-side mod like Wurst can just remove.
Hope that clears things up!