10 DME ARC, yes, I understand how it might increase arrival rates if you use a trombone, and the fact that doing less vectoring reduces controller workload, but I still can't see how - mathematically if you like - having all your arrivals one behind the other on the same route can lead to closer spacing on final than having your traffic on a variety of routes, using a combination of vertical and lateral separation, which then gives greater flexibility in getting them on to final with minimum separation.
And in any case, isn't the ultimate determinant of arrival rates always going to be wake separations on final?
The more I hear the more I think GASA's right.