I actually think this test is more "real world" than many of the other tests I've seen. The roller tests in particular seem very suspect to me.
After all, one thing most owners of AWD cars expect them to do is get them home from the store after a snow or ice storm. Launching with all four tires on an icy flat surface is one of the more basic tests one could do.
I'm not all that surprised by the results. With no limited slip differentials at either axle, it's all down to the software, at least for launches. Looks like the algorithms have been figured out.
Having said that, it would be interesting to see how stable the two cars are at speed (say, 35 mph) in a corner on a hill. Particularly, when the surface changes from wet to packed snow mid-corner. Now
that's a real-world test. Theoretically, Subaru's more even torque split and "always on" AWD should give better stability (less likely to drift off-line) than a system that is FWD by default. But then again, it probably depends on how fast the software intervenes.
I'd also like to see the test in the video done with a OB with a limited slip rear diff, but I don't think Subaru sells cars like that any more.
Finally, agreed with all the comments on the tires.