are you kidding! There would never become a negative thing out of this. They might not be playable? They can easy change the rules, there are some not legal cards and why not make these cards non legal if it makes people leave pokemon?
Anyway, i think its cool. There is the same thing in the games, where its like impossible to find a pokemon that have 31 IV in almost every stat except one. if someone (or hacking) find this pokemon, they have the advantage. So, it´s as the same as the games.
There might be more strategy to the game when they make these cards becuse you wont win becuse the pokemon got less weakness and more HP. There might be something else that makes it fair, like less attack or no resistance or something. dunno.