Hot methods are not really well visible in the flame charts, so I has a idea to improve them...
I really like the result:
The UI is quite usable, I was able to detect and fix several performance issues in real production code already.
There are a few things to be improved on the UI, but over all it is a big step forward!
Other approaches are to use graphviz to visualize call graphs as suggested in:
which seems to be the way they are visualized at Google as well: