I originally felt the same way. I do wish there were one or two more "sloppy" legato transition styles, and a light portamento version, too. (Here's to hoping that VSL may be willing to add such transition styles in the future?)
However - after really sitting down with the legato this afternoon and giving it a serious open-minded chance, I am beginning to really like the legato styles that they have provided. In particular, I feel these legato styles provide *controllable* flexibility. I can see how this will be useful in a wide range of music, working more broadly than sloppy legato transitions would (even though I'd still wish for the sloppy/portamento options, too).
I just uploaded a legato demo in a separate post, too. Jimmy and Stephen, do you feel that example has the same problems that you are describing here?
Stephen, about your Berlioz example -
You might already agree that getting realism from sample libraries always requires trial and error between velocities, crossfades, and articulations, often using unexpected articulations with unexpected velocities to get the right nuance. For me personally, this is a game I'm willing to play, and I hope that Synchron Player makes it easier to play that game, or at least doesn't make it harder to use wrong articulations that surprisingly might work in unexpected places =)
In your clip, it looks like there's not much velocity xfade action going on. I bet it would open up a lot of possibilities to vary the velocity xfade more dramatically - to sculpt attack/development/decay of individual long notes, or over arcs of notes in one bow stroke. You probably already have tried various different legato articulations with trial and error, but my feeling is that if you just trial and error some more, it could work. One particular example that really sticks out to me is around 0:40 - 0:45. instead of using slurred legato followed by the long patch, I suspect it would sound better if you used normal or fast legato, followed by short sforzando articulations to mimic a detache with a slight attack. In some places, I think you might consider using other articulations than legato, too, where a more crunchy attack or a light release are needed - those details sometimes add more realism than a legato transition would, especially on beginning/ending notes of the phrases.