From the interview we had with them last year, and reflecting Birgir's point all along, there's no magic bullet though: the size / weight are bound to go up if you want to increase the drive capability while ensuring stable operation.
I don't know the details on what Birgir plans to do to the 007t, but it seems along the line of pushing it further into class-A by increasing the idle current and the dissipated power at the same time? It may work better but the case wasn't designed to dissipate as much heat.
For Stax, the current amp they're working on does require new sinks / new chassis to fit in properly and dissipate the heat.
The differences in feedback topologies between 717 and 727 are a matter of taste and a designer choice and there does not seem to be one better than the other. When I asked them if they would be keen on providing the user a switch (like was done with the latest kgsshv version), they said no way it would happen.
Arnaud