I frequently modify streets as the first editor currently since I live in an area where many streets are still created by admin but unchanged ever since, so most of the streets in villages have the directions still set to "unknown". When I change them to "two way", I would like to be able to set in the same step both nodes to "allow all turns" instead of first having to edit the directions and aftewards both nodes separately.
I would like to have this option for two reasons:
It saves a lot of time since at least in my area, one-way streets are fairly uncommon and so most of the time, all turns are allowed and it is easier to change back to disallow something for the rare occasion where this is needed.
More importantly, I think it reduces the number of errors since when I need to do things in two steps, chances are I'll forget to click on a couple of nodes and thus, some turns remain disallowed that should be set to allowed.