I actually like d3 (Mike Bostock does some insanely awesome visualizations with it), but maybe I've not yet come across a d3 charting library that makes it easier than manually computing my SVG offsets to make it not such a huge runway to get a configurable chart up and running without reinventing the wheel. When you say d3 charts, do you mean d3, or some charting API (not sap.viz charts, though) that you like? I'd be interested, as I'm not married to a charting API at this point.
I chose Highcharts at random, but I'm more interested in sharing my approach on how I am using the tuples and data in the DataSource ResultSetCell Selection and Metadata properties. The charting API could be anything (I think I like FusionCharts better, to be honest) Also I like DevExpress's ChartJS.
However, the approach would be the same -- Take some multidimensional data, pick a dimension for the axis and series designation, adapt it to fit the charting API's format (probably big-picture via an AdapterAPI to abstract it away) and then spend some time building a properties panel to customize the chart. As we've seen, the charts from SAP are not very configurable out of the box. Things that bug me like control over the legend and how to handle excess dimensions I was able to address via SDK.
If I can ever stop long enough to put the blog together and publish it, it'll be jammed with lots of more information.