I understand what you're getting at.  The old torts of assault and battery separated the crime into the attempt or threat of using force against a person versus the actual physical force, the battery component.

But it seems pretty clear in Canadian law that determining the actus rea of sexual assault under S271 requires there to be touching, that it was sexual in nature, and that there was no consent.  

It's only under S272 that threatening a sexual assault with a weapon is sufficient to establish the actus rea of sexual assault with a weapon.

Which is why I do believe a verbal threat of sexual touching (without a weapon) would be prosecuted, if at all, as a common assault.