My major concern nowadays (which never used to be a problem) at Japanese airports for arrivals is the very long immigration queue.

It took me 55 minutes last time to get through immigration queue* at HND (no fast track for J/F seem to be available there, whereas some airlines offer it at NRT for F), and the previous time was 40 minutes. The one before was about 40 minutes too.

Whether I simply ended up at unfortunate times or not, the immigration queues are the biggest bottleneck at Japanese airports now. They used to be so quick and I used to regularly go from the aircraft pulling up at the gate to getting landside, including collecting bags, off an international flights in 20 minutes but those days seem to be over.

*Time from joining the queue to reaching the immigration desk. Non-Japanese passport, non-visa national.