I mostly agree, but you forget about one thing, the axial database, EXP07 would add a total of 100 Brass and sax sounds of the highest (including supernatural) quallity..
Bachus, sorry to correct you, but you are wrong there about SuperNatural sounds! You would be very shocked to find out after buying the FA: You CANNOT add supernatural sounds to it from Axial or anywhere else. The EXP-07 is identical to the SRX-10, you can check in your Integra: it has orchestral trumpet, trombone and French horn sections, but no solo brass (except tuba) and no saxophones. All the EXPs are identical to the former SRX boards, and none of them have superNatural sounds on them. And there are no really good saxophones on any of the SRX boards, there are fairly good ones on SRX 03 (EXP Studio), but they are bay far not as good as those from BK-9/7m, which were obviously samples by Roland Europe, as I don't know any Roland synthesizer on which they appear.
The other Axial collections you can load into the FA (besides EXP) are merely reedited sounds based on the SN-Synth waveforms that are already in the FA.
So, it is nice that you can add something from the SRX library, but they don't include SN-A sounds and there are only two slots for EXPs.
I checked thoroughly when the FA came out whether it could be a replacement for the Integra, but it isn't.
All in all, the BK-9 offers the better range of acoustic sounds, unless you are very keen on two particular SRX/EXP expansions you could use in the FA. FA is better for symphonic sounds if you use EXP Orchestra plus Brass or Strings (problem: all 3 are impossible), probably better for E-pianos, and certainly for electronic sounds. For acoustic sounds involved in some pop music, swing, jazz, latin, oldies etc., you are certainly better off with the BK-9 soundwise.
Why was the BK-9 so unsuccessful? - It has not much to do with the range of sounds, but with marketing, Roland's present image as an arranger manufacturer, the look of the two tiny displays, shitstorms and the fact that Yamaha boasted with their audio styles in their demos, which sound better than the BK-9.