Thanks for the insight! I have thought of many of the cards, and the theme sort of developed from there, as it fits in with the cards, and fits in with the idea of dominion, and even the dominion story (if one can call it that). You know, Prosperity: the prospering kingdom, a little later, Hinterlands: the expanding kingdom and venturing out, and then next, Tyranny: forging alliances and making enemies with surrounding powers! (This again is just a general idea, strictly speaking dark ages [then guilds] came after, which provides for an interesting story.)
I agree, I think will just give it a stab thematically, but focus on card functionality, since that is the most important thing