highway=traffic_signal nodes just before crossing=traffic_signal are redundant and would not solve the issue of a vehicle passing several traffic signal nodes in general.

"we need to ensure that vehicles only passes one highway=traffic_signal node no matter how they turn" - This is a new issue which this original changeset did not solve.

In the common case you cited, only one short section is necessary. The entire intersection is mapped by 6 relations.
I don't think the data is much more complicated. Instead, the reason that via-ways are not implemented is that the latter complicates the route search substantially.

I think that it is important to ensure that the data users (software) can correctly consume the data. It is not much useful to map data which nobody would (yet) use. (If I had used via ways from the beginning, the map is now useless for routing.) On the other hand, once most routers support via ways, it is not difficult to simplify all intersections automatically.

This changeset was doing the opposite, putting highway=traffic_signal besides every pedestrian crossings (not at the intersection node), while removing the existing highway=traffic signal tag from the intersection node. Isn't these equivalent?
Anyway the existing state as restored should be consistent with your statement?

Please do not delete the existing tag of amenity=bus_station and naming convention (short form for name) which is in use. Just using public_transport=station for bus terminus is (1) not rendered and (2) not clear what type of station it is.

As a good practice in general, please keep the existing node as a part of the new way if you upgrade a node to an area, to keep the edit history.

What do you mean by light-controlled pedestrian crossing without vehicle traffic light?

Yes except that no today routing software (perhaps except a new trial build of osmand but not tested) understands via way. Almost all existing services using OSRM, etc and existing apps will be broken.

highway=crossing and crossing=traffic_signal already implies traffic signal. No need to add another highway=traffic_signal node a few cm from pedestrian crossings

Don't think this should be encouraged although it might not be illegal. Checked transport department's e-routing and it does not advise U turn here. It should be up to the driver to take the risk.

Breaks routes 2 & 68X

Messed up the intersection btw Pokfulam Road and Smithfield seriously

Thanks for reverting 28583594

Which router ignores vehicle=no? Anyway changing from service to motorway_link would only increase the chance of routing through it.

A number of these short sections are necessary to enforce prohibition on U turns across dual carriageways. This particular changeset removed the restrictions to prevent south bound vehicles on Lai Chi Kok Road to make a U turn, and in addition damaged restriction relation/1466083 which prevents right turn from south bound Lai Chi Kok Road. Need to be reverted

Only the outer polygon(s) of the feature (reservoir in this case). The large areas of woodland to both the north and south of the reservoir is not part of the reservoir (nor part of the 'hole' to be carved out), and therefore should not be included in the relation. See osm.wiki/Relation:multipolygon

The multipolygon represents the reservoir. The woodland should not be added as outer. Fixed in Changeset #26682125.