Ok , I will chine in
Rockers , foil are similar
Bottom contours of the BB are what I think will make it a more versatile option. Shallower concave and vee out the back with keep it free on the open faces of the reefs
The Ghost has more single and that only really shines when pumping thru toobs and hind legg carves on critical parts of waves . Kinda sticky when not being aggressively pushed
My .002 cents out
If that is based on real experience from riding the BB and Ghost then it is worth more than .002 cents to the prospective purchaser.
I'm reaching similar conclusions to you regarding light Vs deep concave. It only takes a few mm of concave to make it more reactive and able to sit high on the surface when some easy speed is needed. I used to theorise that the deeper the concave the more reactive and more sit on the surface lift - but it seems not. Instead the more turned down rail of the deeper concave bites more - this based on a chance encounter and conversation with surf journalist Nick Carrol at an uncrowded day in Bells - he was happy to chat and turn his Maurice Cole surfboard upside down to show me. He said despite the deep concave the board felt "very normal". So could not have been super reactive and skatey.
My toy step up has what I would describe as a light double inside a moderate single concave, but not MC deep. I haven't seen a Ghost, but somewhere in this message board I asked Maz to run a straight edge over the underneath of his and I think this is what he described. My toy step up feels like it has less lift than my two lightly concaved HPSBs. I do get the push back of the concave though. However, there are things not quite right with my toy step up (self build).
I don't think V in the tail helps on open faces though. Light concave or flat helps that. I am speaking from a mixture of experience and theory - the trouble with experience is that we don't have the time and money to just change one thing, so when comparing a V'd board with a non V'd board there are other things different too which confuses the comparison. As for theory I might be getting that wrong. Anyway, what I think V does is kill a bit of lift, so helps things keep under control in more critical steepness and power. It also helps bank the board over at speed - this is more important in wide squash tailed boards and the Ghost is both narrowish and rounded pin, so banking it over from the back foot shouldn't need the help of V.
Another possible explanation as to why the Ghost likes steeper waves and more pumping is that it has high rocker (I don't know if it does), but high rocker boards do seem to need more top to bottom pumping to keep them at max speed.