poison should be super effective against normal, grass, fighting and bug types
My thoughts exactly. Well, OK, I also think Poison should be super effective against Dragon, but that's less "logic", more "for the lulz", know what I mean? Oh, and Water, naturally. Poison would become one of the best offensive types in the game, it would be like a dream come true for me.
I think poison needs to be SE on steel, steel is such a strong defensive typing anyway let poison be turned to acid and eat through the steel. Then poison will be able to see a fair bit more usage if only so it's not completely stopped by one of the most common defensive typings. In addition I agree that toxic should be stronger if used by a poison type, make the drain faster for a poison typing using toxic. Finally Poison types should heal from being hit by poison type attacks.
I've got a quote that embodies you perfectly, but it's seventy-three posts long, has a few massive flowcharts, and lots of Xion-KMA to Me