This feature is really great, and I would love to see this expanded where we could distribute probability among the sets.
I'm unsure what the exact logic is for the current button, but at the very least being able to turn that on and off by set would be great. Also a "less." Of course, my first suggest of a generalized continuous probability setting would be ideal.
At the moment, this button guarantees 4 Menagerie kingdom cards and one Menagerie landscape.
Since this is an automatch option, I don't think this will get much more complicated. Otherwise the people who want 10% more Intrigue than normal could not be matched with the people who want 20% more Intrigue as normal, etc.
One possibility would be "extra X and Y" where each player nominates one expansion, so you get more cards of your choice, more of whatever your opponents choose (without knowing in advance) and less of the rest. I could then automatch a variety of Alchemy-heavy games, but with a variety of other people's choices