Really unhappy with Johnny Quick and Atomica's origin flashback In two pages, they:

Brag about killing
Brag about breaking someone's neck and beating them to death,
Make two cops fight each other to the death under threats to their families
Brag about how they're going to torture and kill their children anyway

Then, there's how they get their "powers". They're at Star Labs and lightning hits the building. That's how. That's it.

It feels like a waste of space. There's a level of depravity that just seems so uninteresting and a waste of an opportunity to write better characters. Then the whole "crazy kid killers in love" is just irritating.

I commented on Geoff Johns' realisation of Earth-3 elsewhere but in short I do agree with you. The idea that drives Earth-3 and the Crime Syndicate is of an earth that is the moral opposite of ours, a dark world, but it's not just its morality that is skewed.
The problem I am having with Johns' realisation of this earth is that it has no subtlety whatsoever, evil is capable of being manifested in far more imaginative and callous ways than the simple mass murder and genocide we have been dished out with, but that subtlety Grant Morrison brought to the Crime Syndicate's revival isn't a level of imagination Geoff Johns is capable of delivering anymore. It really pains me to say it as I've been a "#1 fan" since he arrived at DC, but his writing these days is not great. It is getting progressively worse.

Aquaman is the exception.