I find this an interesting move for two reasons - the impedance issue and the "coloration" issue.
I've always understood cab impedance to be very nominal - although its quoted as an absolute value, in electrical terms its anything but. And I've experienced problems from a reputable manufacturer slapping an 8ohm label on a cab, when the driver inside was labelled 4ohm. I had no idea why my amp was going into thermal protection (with a pair of 8ohm cabs) until a few years later, when the driver came out of the cab. The modular 2 or 4 or 6x10 makes perfect sense to me.
I've now tried several of the modern "flat response" type cabs, and I find them hard work to eq. I prefer the "musical response" built into cabs like the Bag End S15, and most of the old SWR boxes (although they can be a bit too voiced). I hadn't expected to see BF go in this direction, but I expect they will will do it well and only produce designs that work in the gigging environment. The original Compact had a very useful voicing, so now they have more control over driver design I assume they can also be more accurate in how far they go with neutral/voiced cabs.
Looking forward to seeing how this goes..
PS - I'm waiting for a powered Super Compact...hint hint...eh?