This is brilliant, and a much more flexible and high value use of the existing fields - it is also consistent with how most email calendars handle their events.
Would now be a good time to remove the Minimal Event option?
Is there any interest in extending “Location” to include pre-defined/centrally managed locations and, ultimately, room management? E.g. a “room” can only have 1 event occurring in it within a given period of time, so sort of room “reservation”, etc? This would be a huge feature for enabling conferences, but also potentially managing events for real-world communities with associated spaces.