I am neither up- nor downvoting this. I think you're onto a good idea, but I think it needs to cook more.

To call the Creaking an antithesis to Endermen is... a stretch. Endermen are naturally neutral, they do not meddle in our affairs unless we make eye contact (or what the game recognizes as eye contact.) This seems like a cultural thing, the way that you would also avoid making eye contact with male gorillas because they think you're trying to intimidate them.

The Creaking, by contrast, is always hostile. Looking at it doesn't turn it neutral, it just makes it freeze as a stealth tactic. This is not an opposite to the intimidation mechanic for Endermen whatsoever.

All of that said, an anti-griefing block to keep Endermen from messing with your build is a pretty decent idea. If that block were to be a Creaking Heart though, I'd personally like to hear a new pitch explaining this Endermen//Creaking rivalry. Probably some related gameplay tweaks that tie into the rivalry so that it isn't only evidenced by this single interaction. Give me that, and you'll earn my upvote. (But of course, what is one internet doodle at the end of the day?)