If functionality does not currently exist for this, it would be helpful to have a simple (yeh, right...simple) place to enter notes about each recording...perhaps under the "insert" tab? For instance, I record frequently using an H4zoom. I import those recordings to Reaper and augment them. It would be helpful to enter notes that I'd done that. Eventually, I'll forget.
Another example. If I accidentally recorded a certain track that sounded great. I'd like to document exactly what I did. Again, otherwise, the "good miss" (aka, accident) will be forever forgotten.