There is an existing request to add caching of reports for a certain time. Even in the app, they will still have a timeout. For example, there's little point to keeping a police report for more than 30 minutes. Likely has moved on well before that. So that kind of report would not get uploaded at all.
So, in short, yes, we and Waze know we'd like this feature. When it may be implemented is uncertain. Waze still focuses on the daily commuter market. This market almost exclusively drives in data coverage areas. Also, if a feature works for 80% of drivers on a daily basis, it is likely not to be changed. So unless more than 20% of drivers are affected by lack of report caching every day... don't hold your breath.