This is something I've struggled with--a good method for storyboarding branching scenarios. I've used several different Word and PowerPoint templates in the past, none of which have quite worked the way I wanted. I can write the branching in a linear document without much trouble (I once drafted one longhand in a notebook), but it makes my SMEs brains explode to try to follow them. I've seen recommendations for Twine in the past, and this explains in more detail how it works as a storyboarding tool.
Online Quality Assurance Reviewer. Awkward name for a product, but it does similar functions to ReviewMyELearning. Reviewers can comment with each page of a course and IDs can collect feedback from everyone on the team. Unfortunately, they don't have a free trial, so there's no way to test it out and make sure it works for your courses without paying for it.