I think that technically, the program is very good.
The reason the images doesn't look 100% realistic,
or perhaps I should say naturalistic is, apart from
what has already been mentioned, the fact that the
growth of real trees are controlled by nature.
Ie where it stands (winds & soil) and the access to
light and water.

The most important factor would be light and water.
The water controls how much the branches grow, and
light controls how they grow.
So what is missing is the "distortion" of the algoritm
that occurs when the branches turns to take advantage
of the light.
Thus the scrambling isn't random, but depend on other
branches, direction of light etc.
That is why the mesh editor is so important, because
it enables you to remove the branches that "looks"
wrong.
Perhaps this problem could be solved by a growth
simulation, coupled with an attractor (representing
the light).
I'm not trying to criticize the program or anything,
it just thought it would be an interesting topic.

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