Though I have strong Austrian sympathies myself, this tree drastically overemphasizes their importance (and misclassifies Tyler Cowen, who hasn't been an Austrian since his first year in grad school if I remember correctly). There are a dozen economists who should have been listed on the other side before Pascal Salin, and many dozens in the modern era before Reisman and Salerno. As much as I love Boettke, he's influential primarily as a teacher, which sets him apart from the rest of this group.
I'm disappointed (though not surprised) to see Marx so marginalised. In particular, Schumpeter was in massive debt to Marx, as is quite clear from reading Capitalism, Socialism and Democracy. The whole idea of creative destruction, for example, which is popular up to the day, is basically lifted straight from Marx. Of course, the evolutionary economists who consider themselves in Schumpeters legacy, tend to ignore this link too.
The creator seems/seemed to be taking suggestions to improve it. I'd encourage people who have improvements to suggest to suggest them, and/or create their own version using their own tools e.g. graphviz.