...is one that will be X-platform. i.e. I can use it on my desktop or tablet. Music making is no longer by appointment tethered to my studio. Rather it is always with me on the go. I can do some fiddly editing while waiting at the doctor's office. I can set up a mixing section in the subway. I can share project files across platforms using the cloud.
If Sonar isn't the first and someone else does it, then this is the only feature that would make me switch. It would be revolutionary in my music making.
So Cakewalk. Please take this as a feature request for X3.
PS- I have an iPad. So yes mac compatibility is a must for this functionality given the dominance of iPads.