My summary fields tend to be quite long, so that showing them in the main view would make it unreadable as a timeline. It would be very useful though to have an option in the view options - the “customise item card” menu - to have a summary snippet in addition to the summary, which just shows the first two or three lines of text, maybe expandable.
I considered adding a property called Summary Snippet to do this manually, although it would be pretty tiresome to copy and paste for every event and decided it would be a waste of time to do it and maintain it over developing drafts. In any case, I couldn’t see how or whether it is possible to add properties to the customise item card menu.