dual volume controls?

The Quicksilver full function preamp with it's stepped attenuators is a pleasure to use. Mike Sanders would not have chosen this design if he didn't think there is a benefit to it.

I found the Audible Illusions preamp without stepped attenuators very frustrating to balance. I gave up on it after one evening.

Needing a balance control does not always mean there is something wrong with the system. More likely than not it is a room problem that may be too difficult and expensive to cure. Very few audiophiles have the perfect room or even a decent room as is evident in system photos on this forum. In most cases the presence of a balance control is much less harmful than the room itself.

Sounds more like an opinion than a fact.