Is Magento 2 still an ungodly nightmare to work with?
The backend is closer to what PHP developers using other frameworks (symphony, Laravel, etc) are more used to. The conventions make sure you have to write cleaner code. M2 is catered a lot more to backend developers than frontend developers, so I think in general those who have worked on both tend to like M2 better. I agree with you though, it is slow when running it in development mode. There is a lot of overhead that comes with all of the compiling.
Agreed about the frontend being a mess in the Luma theme (but so was M1's frontend, prototype really?). That said, PWA studio is very promising, basically Magento is throwing out their Luma based frontend, using Magento as the backend server, then new builds will use PWA and have headless frontend. The frontend won't care at all about how the backend is implemented anymore because it's truly headless. Your frontend developers can now focus on the frontend only, and really, do whatever the heck they want there regardless of what Magento does. Same goes for your mobile app developers, etc.
The way things are moving though, everything is moving in a very "enterprise" like direction. Magento isn't going to be as suited for the mom and pop shops moving forward since they'll have to pay, more than likely, for a custom built frontend to be developed.