I've never been that happy with the output from any of the different graphviz engines. I'd like to see a UI graph editing tool which can import and export .dot format, but also allows manually moving nodes (which I guess wouldn't get exported unless arbitrary metadata is supported), and ofc exports to svg. Maybe there's already something similar I haven't stumbled across yet?

I guess my use case is mainly swimlanes and places where nodes don't have to have the same rank.