Simulacrum: It just breaks sooooo much stuff. It's buggy, and 99% of those bugs are from getting it from a random place. And also, it's confusing for new players - even if they're playing Apep and it worked fine, they get Simulacrum from their perk 1... which gets them a 7 mana Colossus or something random. That's not a random 2 mana card!
City Watch: Come on, it's 3 crossbow dudes. For the same reason you can't get Nyrvir from a Future Present (getting stuck with a crappy 4 mana spell feels bad), you really shouldn't be able to get CW from a random drop.