Thank you for writing.
First of all, I would like to inform you that RadChart for WinForms is an obsolete component. In Q2 2012 we introduced its improved counterpart RadChartView for WinForms to which have been adding features
and will continue to do so if there is a demand for it. 3D chart has not been a popular request for our charting solutions and currently we do not have certain plans to implement it. I created a PITS item for this request and you can vote for it here
. We may reconsider our plans in case we see that the demand for it rises.
As to your question about the general Telerik WinForms development, we have not stopped adding features and components to the suite, and this policy will remain the same as long as we see that there is interest in the product. In Q1 2013 we released one brand new control - RadPdfViewer, the first official version of RadPivotGrid, and several RadChartView enhancements. In Q2 2013 we plan to release yet another highly requested component. The WinForms Roadmap will be published soon. Stay tuned!
All the best,
the Telerik team