Yes. Right now these cases are essentially coin flips -- will this specific judge think that these two songs sound similar enough that there's a >50% likelihood

Yes. Right now these cases are essentially coin flips -- will this specific judge think that these two songs sound similar enough that there's a >50% likelihood that the defendants had heard the plaintiff's work? Which is why in the long term the only solution for lawsuits like this is to change the law so that mere melodic/rhythmic similarity is not sufficient to file suit.