This would be a big plus for Melodyne and Vocalign users.
I realize this would require a licensing deal to add this functionality but I can’t imagine that the cost is that great that it would outweigh the benefit.
There is no comparison between using ARA enabled products in a DAW with ARA and the old transfer process that we are still dealing with in Cubase.
UPDATE: Per Steinberg, ARA2 support should be added to a Cubase 10 maintenance release sometime in Q1 2019.
https://www.steinberg.net/forums/viewtopic.php?f=283&t=147132