It's true that this could be implemented. I already proposed such a feature, but theultramage was against it. The reason was, that such a feature was never intended in the game design. I agreed on such argument and because of that it didn't get implemented.
Also, the change in the system would be probably larger than you think. Executing card action is easy, because it happens only when card is played, but discard occurs not only by standard discard, but also via card effect. So, in other words we would have to support a feature which would allow a card to execute card effect of some other card. I don't think this is such a good idea.