On the change to `highway=corridor`, I don't think it's worth it at the moment. The wiki ways that 80% have[had] a `indoor=yes` too, so I think that's where we look instaed of highway corridor. These are normal and often important/generous footways, but the problem is  osm.org and indoor maps don't even render `highway=corridor` and sone routers ignore it. 

:(
It's not ready for primetime, imo.

 The corridor tag we can go for is `indoor=corridor`, which is best done as an area. Along side each `indoor=room`, `room=shop` thingos.

Look how it looks [on OpenLevelUp](https://openlevelup.net/?l=2#20/-31.94849/115.86252) as someone starting out.
OLevelUp inherently misses all navigation features except steps and corridor areas :( so we have to get fancy manually with areas.