I don't see what BB-7 and disk brakes have to do with Bromptons.
As for brake pads, I'm told to use soft pads, since it's easier and cheaper to change pads than getting/building a new wheel, but that doesn't solve the issue of sad braking in the rain and/or steep descents on a Brompton.
I'm also told having to buy/build a new wheel every couple of years when riding a Brompton frequently is not unusual.