Allow Requirements under features to have Date fields. These could be locked to the feature's date range or allowed to fall outside depending on the organization and how they manage.
This would allow for more granular reporting on Features, or to have Features automatically set a date range based on each Feature's requirements opening a new workflow process to build features from requirements or vice versa. Lastly this would provide deeper use of reporting from Aha! without having to deal with the external work of combining spreadsheets from project teams.