We are already producing JSON output from our reporting application, and would like to know if you have a generic chart builder planned ? This would work along the lines of letting the user select a data source (i.e. JSON data), then select the type of chart they wanted (e.g. line, pie), select the columns they want to create series for (based on the data source selected), the values they want to plot etc. etc. Other options for themes, titles, colours etc. could also be made available.
The options selected would be stored away so the chart could be automatically re-built based on the users selections at a later point.