Still, looking at the exact same kingdom is pretty useless.
I mean, replacing a card that isn't bought by another card that will not have been bought has 0 effect on the actual game. Can you say that these people played a different kingdom? Yes, but you could also say they played the same interesting subset.
Now I'm sidestepping on a road where it's pretty hard to quantify stuff, but I think two different kingdoms where the exact same subset of cards has been purchased has been played.
Obviously, you can play Big Money in any kingdom,, but that's a bit lame. The skill of the players is also a factor. I think good players are better at deciding which cards in the kingdom should and shouldn't be bought. So if a newbie always buys Talisman, does it really count?
It's still an interesting discussion point I think.