I think it is certainly worthwhile, and I've already used one of your new features in the d3-hierarchy package (d3.stratify) in a d3 v3 project. I think the gen

I think it is certainly worthwhile, and I've already used one of your new features in the d3-hierarchy package (d3.stratify) in a d3 v3 project. I think the general improvements are enough to warrant the breaking changes. I think you will see a brief period of a python 2/3 syndrome, but I think it will pass quickly. Thank you for working so hard on this Mike!