The current hierarchy is either too high, either too low for adequate product breakdown, and hence create difficulties in work assignment and follow up.
Initiative to Epic=ok, Feature to Feature, ADD User Story level in between, Reqs to Reqs=ok
Today, we have introduced Master features -- a powerful new capability for your bigger work items. These can also be used as epics to group your stories.
Read more about it in out blog post: https://blog.aha.io/epic-roadmap/
I don't really understand this request... there are To Do's at every level that can be used for intermediate items. You can also re-name the terminology used for each item to fit your workflow better.
You could use To-Dos at any level to provide a sub-level item. We sometimes map Requirement To-Dos as tasks.
If you're reluctant about this, a feauture to feature and reqs to reqs decomposition as exists for product lines would allow for even greater flexibility and likewise provide a more robust product breakdown capability.