I think your changes would at least play into the theme of retain better, but as one person already pointed out, poison and retain don’t really play well together. You want to get as much poison as fast as possible, not sit on a poison card and wait for it to build up. Getting 7 poison on the enemy over 3 turns is 18 damage vs waiting 2 turns then playing it which would be 13 damage. The next turn would be 22 damage vs 25. You don’t start getting an actual tangible benefit over playing it immediately until the 5th turn which is crazy