This is a very interesting discussion. I think the key to a Soloist RT is the link between a certain phrase and the underlying chord. I've heard some RT Soloists play basic pentatonic phrases over all kinds of complex extensions. Other times there will be something like a Gb9#5 chord and all the soloist does is play one note until the next chord change so obviously there is nothing there that encompasses that chord. This is just an observation, I have no idea how that chord/soloist link actually works.
Many of the midi soloists are much better than the RT soloists except of course for the overall sound quality and live nuances that's missing from midi. But as far as actual notes are concerned the midi soloists really do follow the changes better than the RT soloists do.
I think the reason for that is the file size limitation of the RT's. The RT artist would have to play so many different variations that the file size would be too big while midi can keep scrambling and creating note phrases almost endlessly. I say I think because it's just a guess.
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