>>32570706I can't imagine it would be that good; a lot of things ran Blizzard back then, and a 4x weakness would make that worse. For example, with Gen I's critical hit mechanics, a Tauros has a little under a 20% chance to OHKO a Grass/Dragon Exeggutor with Blizzard, factoring in the 90% accuracy.
Plus, like
>>32570724 said, Psychic is a really good type to have in Gen 1.