Used to be, if you determined your deck had a weakness to poison, you could bite the bullet and upgrade a purify or two so your non-water deck could still counter poison.
Now, if your non-water/non-rainbow deck has a poison vulnerability, you must completely overhaul your deck to include water? Ridiculous.
We've added a handful of new cards that poison, including the OP scorps that add a poison every time you play a card, and removed the ONE and ONLY card that a non-water deck could use to counter poison.
I realize there a prevalent rainbow-deck fetish in this community, but I had no idea how bad it was...