For those asking, yes, there are some statistics, though I pulled these from vDip, not webDip. The sample sizes aren't huge, but they're enough to be fairly accurate I think.
World IX:
http://vdiplomacy.com/stats.php?variantID=2
The story here is of massively imbalanced powers, where Europe and Libya in particular might as well just drop into CD. Pacific Russia's numbers are only relatively decent because some lucky soul managed to solo, but otherwise, they're basically a "dud country" as someone earlier in this thread said. Quebec and Western Canada are particularly powerful and in my mind the most powerful countries on the board other than Kenya. Both are located in the same area, though, which creates even more issues. It is the least balanced variant on our site and pales in comparison to KW901.
KW901:
http://vdiplomacy.com/stats.php?variantID=57
This has a much larger sample size despite being a much newer variant. That's not a coincidence. It's much better.
As far as average performance goes, there are still a couple of overpowered countries (Srivijaya in particular, and maybe France) as well as some underpowered countries (Arabia is pretty terrible), but on the whole, it compares somewhat similarly to Classic, where France and Turkey have better odds than Austria or Italy (for actual data on Classic: http://vdiplomacy.com/stats.php?variantID=1). The map as a whole is far more conducive to solos, which are the point of playing Diplomacy, than World IX is, and it is in my opinion a much more fun map.
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Situation on the board
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