the SV1 piano sample and the EP sample probably made up the most part of the 'Doubling of the rom'. Korg did the same thing with the triton series where they used half the rom for one decent piano. The numbers game is just that...a game. Yamaha did the same with the XF over the motif XS but you would be hard pressed to 'hear ' a difference considering all that extra memory.
Diki there were lots of new styles in the PA3X demo ,for example there was 'Tower of Power', 'Boogie guitar' ' dont go changing 'and there were a handful of DNC sounds that we have not heard before . For example ,an electric guitar DNC that was mediocre to say the least , a human soprano voice using DNC saying ahhh and a violin using DNC that sounded lame compared to the yamaha. There was also a useable sax and trumpet all using DNC . There was also was a very decent clarinet,harmonica , classical guitar and flute that sounded pretty good but not in the same league as the yammy Sa or SA2 equivalent voices.
You might have missed them as the demos themselves were so poor or you simply did not notice them as they did not stand out and blow you away.http://www.youtube.com/watch?v=hJOGzgexDMQ&feature=related
no one is suggesting anyone in the USA or west can get PA3X now but in eastern europe i believe they are already available. For example there is talk on the Korg forum that it has been released in Turkey already.