Hmmm that is a bit of a bummer. If you look critically/carefully you will see that the haze and fine detail in the background really improved with these settings.
Though you can see some improvement in the main tree, there's little improvement in the small bushes.
I think the main reason for this is that they have lots small leafs and since you have increased the resolution slightly you might have also introduced extra leafs to be rendered which sort of counteracted the AA, but that's just pure speculation.
I think this object is a really interesting one for testing the new custom sampling for AA. Perhaps the noise will be less when reducing the noise-threshold.
Which model is it?
Thanks for trying this out, though not the result we hoped for it still gives an interesting result and gives rise to new things to try

Martin