Disclaimer, I have no idea what I'm talking about.
I don't think it'll change anything. In my mind, there are different tiers of speed that changes how you need to plan your day, and jumping from one tier to the next is what truly drives demand.
For example, one tier is "having to spend your whole day on travel" (like conventional slow rail or long flights)
The next tier is "being able to get use out of most of your day" (high speed rail and short flights)
And the tier after that is "being able to randomly take a trip without losing much of your day" (metro systems, bus routes, local trains)
The maglev will transform the areas around the stations from being tier 2 to being tier 3, in other words it'll be like a metro line (but much more expensive, which may change things a bit). However, the vast majority of users will still be too far away from the stations to get to tier 3, they'll still be in tier 2 with needing to spend a considerable amount of time on the metro or local train first. The tier jump will only be for a small number of people who live close to the stations.
Without the tier jump, it won't drive demand much, and it won't have much of a transformative effect on Japanese society. People may prefer it for the higher speed, but it won't change how people think about travel, so the number of travelers won't be much higher than today.
It could, however, move far away places like Hiroshima from tier 1 to tier 2, though.