[Tagging] importance=* tag (for transportation etc)

[Daniel Koć]

I have just read on WeeklyOSM that OpenRailwayMap may start to use 
importance=* tag for ranking railway stations instead of 
railway:station_category=* :

http://lists.openrailwaymap.org/archives/openrailwaymap/2016-March/000408.html

The proposition is 7 years old:

http://wiki.openstreetmap.org/wiki/Proposed_Features/Importance

and is quite generic. I think it would help for example with rendering 
airports without resorting to less clear properties like size:

https://github.com/gravitystorm/openstreetmap-carto/pull/1734

and it would be good to have universal scheme instead of 
railway:station_category=* or flights_range=*. Looks like it is being 
already used and quite popular:

http://taginfo.openstreetmap.org/keys/importance

What do you think about making this scheme official?

-- 
"Завтра, завтра всё кончится!" [Ф. Достоевский]