I don't have P7 to compare and see what you mean that now the hair is more thin/whispy than before. I'm guessing that the interpretation of hair has changed.

Nevertheless, even if the actual value of hair thickness is interpreted differently, it is still adjustable. Have you tried making it thicker?

Another thing that may have changed is the result of "opaque in shadow", an option on the Hair node in the material room. And the notion of what is "in shadow" is probably different than it used to be. Since hair rendering is much faster now, I have to believe the rendering algorithm has changed, which means you may have to adjust things. It could mean there is no way to adjust it to appear the same as it used to be, but I doubt that.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)