change would be easy to back out if it wasn't helpful or caused problems

But we've already tried such experiments with "replace me" templates and they were pretty lousy failures, IMO. I don't see a reason to repeat nearly the same experiment again in hopes that it will turn out drastically different.

Hopefully they wouldn't start typing at random points within the midst of the template.

Um, your template actually calls for them to do that.

BTW, we still have a bit of an experiment running on one "instructions inside templates" idea. If you want to get a tiny taste for how often people post without paying attention to such instructions, just visit this search spec and then submit it. And realize that only users who have a discouraged configuration even get such instructions and that the instructions were such a failure that code had to be added to try to detect when the instructions were not followed.

So many features had to be implemented to work around how badly the "instructions" worked, that I don't believe the instructions have much net impact any longer. And we completely gave up on the hope of getting people to remove the instructions in the template (by turning them into HTML comments so we can just ignore the tons of nodes being posted with the instructions still in place).