I'm not convinced that cmi5 will properly "replace" SCORM either tbh... we're seeing more users interested in developing their content within the LMS platform itself or using browser-based content authoring tools like H5P instead of using standalone "desktop authoring tools" that generate zipped content packages. 

There are definitely some "nice things" about both cmi5 and Xapi, and it might make sense to improve support for them in Totara, but personally I'd like to see better authoring tools built into the LMS itself.