At risk of sounding like a mindless futurist, I will say that the Transit App has considerably improved my experience of public transit in the US, because it doesn't tell me when the next scheduled ride is, but instead when the next actual bus is, based on realtime data provided by other Transit users onboard the vehicle.

The only time in recent memory that this screwed me was in SF trying to get a Muni that I thought was a surface route and was in fact underground. So I was standing at a trollybus stop directly over top of the station where I was missing my train.

The one major gap I still feel a lot as a visitor is wanting a transit-aware business search. In Google Maps the "search for X in this area" is a completely distinct workflow from "how to get to X by <mode>", and implicit in the first workflow is that you can infer how long it will take based on the crow-flies distance. And that assumption is very much not true if you are using transit. For example, I would love to be able to be like "show me three-star hotels ordered by transit convenience to X airport and Y event venue" and have it figure out both rides, and call out which ones will have what service level in the evening, overnight, etc.