Tom, I think that we had this discussion back in the old days of the Pro Edition Performance Set (and for once were in total agreement!!!!!). I think that the legato is now much more consistent, but agree that sometimes one would like less of an abrupt change of note. In the real world not everyone would change the bow at the same time, so this would automatically occur. I think that the answer does lie in the release times. You can set this to a controller (I think) and then when the tempo warrants it just raise it slightly so that the notes have a more smooth transition.
However, just thinking about it, if you are playing legato and not getting the legato transition, then this means that the legato threshold is not correct for you. In GS3 (and the Performance Tool) one could change this, but as I previously asked it is not possible in VI. I hope that they change this at some point, as I also like such things to suit my playing, after all it has taken many years to develop my keyboard technique and I don' see that I should have to re-learn how to play at this stage of the game.
DG