It would be valuable to be able to chart date fields by groupings like, month, quarter year, without needing to use calculated columns.
There are so many use cases for charting by date fields. Allowing your users to quickly change the date field grouping from exact (the current OOB option that is really not usable since individual dates are too frequent to chart) to a standard grouping like month, quarter or year.
One solution option that could be very helpful is when a date field is picked for the X-axis, to have an option to use a "group by" of exact, month, quarter, year.
I think that would make line and bar charts much more usable and powerful.