Mostly its due to his short papacy (33 days). Basically when a new pope is elected, it takes a few weeks (at least) for them to settle in and get used to the routine enough to start making adjustments.
In the case of Pope John Paul I, he was installed on 3 Sep and died on 28 Sep. Most of Rome normally goes on vacation in August (in part due to the heat), but this got delayed for many because of the conclave. So about the time everyone is getting back to work, he died.
Again, due to the shortness of his papacy he wrote no major documents and only 1 speech (as I recall). Because of that, his major goals/vision simply isn’t that obvious - he just didn’t have time to tell us.