Thanks for the feedback. Glad to see so many people are excited about the timeline!
As of right now, the most complete documentation for the timeline is in the release notes for 9.0.149. Since then a few more small features have been added:
* Create event for a thought/link via the thought/link context menu
* Preference for starting weeks on Sunday or Monday
* Locale sensitive date and time formats
If anyone would like to step in with their own interpretations of how to best use it, we would all love to hear your thoughts!
Maybe I am missing something here, but from my perspective you can "SET a 'thought date' for each thought" right now. In fact you can set as many dates as you want for a thought - by attaching an event. Simply right click on the thought and select "Add Event."
As for searching by date, that is essentially the entire purpose of the timeline itself.