The customer success team suggested I just use initiatives for user journeys and master features for user journey steps, which is a good temporary fix. However, defining a user journey is a pretty specific thing that I think should be set apart from initiatives for a couple reasons:
Thank you for your idea. In addition to the option mentioned of using initiatives, another option would be to create a custom field or custom table (for Enterprise+ customers) to capture the related user journeys. The benefit of this option would be that you could associate a feature with multiple journeys (using a predefined tag custom field.) This would also allow you to keep your initiative rollup available to show strategic alignment of features.
One option for visualization would be to create a diagram using mockups. We have done this and it is quite effective.
Given the options above and other priorities, we are unlikely to implement this idea at this time. We hope you can understand.