More RAM is what is needed but also as Sokratis mentions, more assignable layers. This is what gets you that real piano, live violins and strings ...etc. 5 levels would be a nice start and with 2 GB RAM, you could now sample every key at 5 different velocity levels (rather than share a sample with 3 keys or such) and the options now grow even more. Of course, this also means you can now use more Audio tacks too.
With the Ajamsonic upgrade, you have Audio Drums, Audio Bass, Audio Guitars and 2 more Audio - chord tracks plus 2 - Audio lower (i.e. 7 Audio parts playing at once)! This explains why our styles sound the way they do especially with the new Choir voices)! With a 2 GB RAM expansion, you can now have 9 wave tracks for all chords and lowers too ..... That is to say, my entire style will be working off of samples (not Midi bases voices) and audio tracks!!
Your imagination becomes Audya's major limitation!