Don't care what they call it, in my eyes they need to do MORE to the new model before even calling a MK2 - have no issue with the MK2 name, just the minimal amount of new features that you would "expect" in a new MK designation.
FX8 (Rev.B) could have been better, because thats all it is.....an original FX8 with a few revisions, not a whole new model - anyone not aware of this would think that the MK2 is drastically improved...its not.
I would expect a MK2 to have extra CPU, more switches/simultaneous effects, relays etc etc - not the same unit in a different colour with a few subtle operational tweaks..
Like I say, my opinion and thats it, not worth a damn...