By far the most damning thing about Principality and County are that they're boring. If I bought a Dominion expansion and those two cards were taking up slots, I'd be disappointed to say the least. I think it's possible to make a decent "Alchemy 2", or better yet fix up Alchemy while expanding it to a full-sized set. But you're going to have to do a lot better than this.
I don't like the title Alchemy 2; it is not my idea, i am not the thread starter. I added only Principality and County as an addition of Alchemy's idea or discussion. It is always in my mind, that these base cards are primary for kingdom cards with potion in costs means Alchemy's cards, although it is possible to play only with them (and potion) as an additional winning way (empty county pile wins too). It is similar to colonies and platin:
additional rule for prosperity: „Prosperity includes two new base cards, Platinum and Colony. You can include them whenever you want to; they are always used together. If you want to determine when to use them randomly, choose a random Kingdom card being used, and if it is from Prosperity, use Platinum and Colony.” And yes, if principality and county are the only cards with no other alchemy cards, it is better to play with colonies and Platin as a winning alternative.
And you are right: my personal idea of any potion cost cards I made is to expand Alchemy to a full set. For me it is the pure pleasure, to play any Dominion expansion and fan cards too.
