Hi Laura -- Unfortunately, we are not planning to have a direct replacement for the Story Map Crowdsource template at this time.
While it's possible that future browser updates or changes to related technologies may cause issues with the Crowdsource template, it has been stable for several years with minimal updates. Even though the app will no longer appear in the default configurable app gallery after June 2018 and won't receive any new features or fixes, you will still be able to create new Crowdsource story maps and existing stories created with the template will continue to work for the foreseeable future.
So for short-term, narrow-scope projects (such as using it to kick off a workshop) Story Map Crowdsource can still be a viable option; however, we cannot recommend it for high-profile and/or long-term projects.
Owen Evans
Lead Product Engineer | StoryMaps