I agree that extensions to the existing libraries in the direction of "extended techniques" would be very welcome. Browsing through the "Special Effects" sections of Stiller's "Handbook of Instrumentation" would provide a fairly full list of such techniques. For example, for Flute, he lists:
harmonics
whistle tones
key slap
pop attack (I think this last one is included in VSL's full Flute 1)
However, the current trend with Synchron seems to be a more limited selection of articulations, but with wider, smoother dynamic range and of course the baked-in reverb. That in itself is mostly welcome but it would be nice if a broader range of articuations were also included.
[EDIT]
On this topic I think it would be good to add, for the brass, a wider selection of mutes would be really useful. CUp mute as well as striaght mute. And for the horns, more extensive stopped articualtions, as well as muted ones.