i listened to most demos of SD-7
yes it is nice to have some new lead sounds,

the LEFT hand, accompaniment DEFINITELY is a BIG step down from the Audya
it's night and day, worse in SD-7 in my opinion,

the audio guitars, audio bass on AUDYA adds so much,

yes AUDYA is older as far as OS, hardware etc, but
i'd be crazy to "downgrade" to the SD-7,

now keep EVERYTHING the AUDYA has, update OS, hardware, specs, make it lighter, add new lead sounds as has SD-7,
THEN i will consider the upgrade :-)

MY opinion of course