Am I missing something or is it really necessary to make a weakness "deck" and randomly pick your weakness(es)?
Based on the section in the RRG (112 Weaknesses pg 27) it seems like there is absolutely no mechanical difference between the 20 weakness cards and so in my mind there shouldn't be any need for randomization. I'm aware that there might be differences in the future and/or effects that reference specific weakness cards but I don't believe any of that exists right now (I've only played the first 4 adventures if that makes a difference).