The Kronos is very popular at least according to the main German synthesizer forums, maybe 50/50 with the Motif XF.

Regarding the mid-priced segment, I don't see that the FA could outperform the MoXF. It might sell better than the Krome. The most important thing lacking is a flash board in order to load third party sample libraries.

Regarding the (virtual) expansion slots, it could be the same as BK-9, but with a different sound structure: the BK-9 (like all arrangers) only has tones as the lowest editing level, whereas the FA PCM section most probably has the system of tones/patches consisting of 4 waveform elements (as it has all the sounds of the XV5080, in which this architecture is used). The SN synth section has a system of 3 waveform elements per tone. These architectures are also used in the Integra.