Discussion time!
what you are talking about is actually a flaw with SoGs.
Unlike Bonds they heal you after you attack, meaning getting EM is alot harder, a simple fix is make healing happen BEFORE attacks. i just didnt get EM cause my shards didnt heal till after i won and i was 1 hp away.
This happens to me a lot. Exceptionally frustrating, that the order of operations does not always allow me to bandage that 2HP before my weapon finishes off my opponent. WTF, grr. At least it is not an activated ability, that would be broken.
...But back to the topic, this change would mean that no one playing against a poison deck would be able to get elemental mastery, unless they took up space in their deck to place a purify.
I am perfectly fine with the way it is. I would strongly oppose any change which denies people the chance to wipe the board (a complete victory), yet be denied total victory because they failed to place a single, specialized card in their deck on the off-chance that their opponent had even a single source of poison.
I believe that poison should have the same role it does now: an alternate means of dealing unblockable, cumulative damage that is immensely troublesome to get rid of, yet does not entirely prevent a player from triumphing over it. Without said card.