I do like that you have more control over the driven frequencies on this than on the Hyperdrive. Does away with one of those awkward switches from the first version, the function of the second switch taken care of by more range on the drive control I would assume.
You know, having spent a lot of time looking at the circuit for the Hyperdrive and considering how I'd rework it, I'd have made very similar changes myself, although I would have gone for the HPF/LPF arrangement to do away with the need for a dual-ganged pot - not saying that was why Ashdown did it, but maybe... I'd have made it to fit in a vertical orientation Hammond 1590BB at the absolute maximum though, there's really no excuse for the poor form factor...