For serious audio listening I have IEMs that go deep into my ear canal, block out a lot of noise. For when I want to casually listen to audio (especially in a public setting or the office), I use AirPods BECAUSE there isn't any audio cancellation or blocking, i.e, I'm still embedded into the environment around me for context (listening out for buses, co-workers, etc.).
I hope these new AirPods "Pro" have an option to install a hard tip like the traditional AirPods or at least some way to have a passthrough ANC. Wouldn't it be cool if these new AirPods could enhance the sound around you using the microphones on each AirPod (for true stero, contextual sound)? And for there to be different modes of enhancement, one could be a generic 'boost audio' one for people with bad hearing and another could be a 'reduce transit sounds' mode to reduce the harsh BART squeels and make it easier to have a conversation with people around you. A smart hearing aid or sorts...
EDIT: come to think of it, maybe Apple ARE planning some sort of 'smart hearing aid' feature for these new AirPods. The new watchOS update gives you a warning when you're damaging your hearing with loud sounds... That would be a perfect opportunity to present a toggle for some 'reduce harsh sounds' mode on your AirPods and prevent further damage to your ears. Constantly seeing that loud sounds warning on your Apple Watch could be all the marketing they need to convince some people that they need AirPods Pro around the city to block out nasty sounds.