As someone who has played quite a bit of Hearthstone, I wish he had released his machine learning tool, even though I probably wouldn't use it myself. Such a tool would basically punish people who copied a pre-existing popular deck verbatim, and reward people who creatively designed their own decks to be different from the mainstream.

I think it's worth mentioning that high level players can already do a pretty good job of predicting the cards in peoples' decks. The best players will often experiment with modifying existing decks or building their own from scratch, partially because there's a significant advantage to not using a popular deck that your opponent already knows how to anticipate.

Hearthstone has a funny kind of a sandwich pattern, where the best and worst players tend to create their own decks, but the vast majority of the middle is largely dominated by the same few decks that you'll see over and over again. It would be nice if a tool like this could help break that pattern.