In Athens? Not really.
I spent one night in Exarcheia about 9 years ago. Needing to be in the city early for a hospital appointment I booked a random cheap hotel on the internet. Bad move. As I arrived at the hotel some dudes asked "Hey, what you want mister? Girl, boy, drugs?" That was during daytime. I was aiming to go out for a meal at night but just wrote off that idea.
Nice neighbourhood? Stop talking out of your arse, eh? There are neighbourhoods in Athens you might not enjoy visiting that are better than Exarcheia .
Sounds like San Francisco and pretty much every major city on the US west coast. Drugs on the streets, squatters/homeless everywhere, city doing nothing about it.