The strings are crap because they lack character and are a poor imitation of how a real orchestra is put together. Normally the violas, violins, cellos, and bass strings build up the whole string ensemble "texture". Try putting those sounds together on the KN6000 and it will sound horrible, quite an indication of how "great" its acoustic sounds are.

Technics just hasn't dedicated enough sample ram to the normal string patches, hence in the higher and lower registers all the samples get stretched too far out.

I wouldn't count on much improvement in the KN7000. A good string section alone would require far more memory than is available.