OMG this is amazing!!, I can finally test some hybrid(upgraded/non-upgraded) unstable trio-decks!!, and not always duo like Half-bloods, plus you have a lot! a lot of potential to make greater things with this tool.
Have you ever thought about making a turn-based strategy game(TBSG) like, age of wonders???
http://en.wikipedia.org/wiki/Age_of_Wonders:_Shadow_Magic, I mean with all the original creatures you already have, with all the similarities between a turn-based card game and a turn-based strategy game, magic/mana generation and consumption, i think you are half way!!, plus with the potential of MMO gaming now a days!!, NO LAG INVOLVED, since it's TBSG, you can either make it free to play and charge micro-transactions for elite products, or believe me I will definitely buy something like this.
How the tool you created and the TBSG are related? well, in every fight you have the chance to fight it manually or the AI plays is for you with the units you have, and the outcome is supposed to be the best, simlar this game simulator.
The are other games like this not so bad, I'm pretty sure you already know this, Might and Magic, atlantica online and disciples 2, but I believe you have the potential to overcome them all.
CHEEEERRRSSS.