To be honest, I dislike the whole Synchron story. But that's off topic here.
You're right about single key switches, but that's exactly the strength of VSL that you can deal with extremely precise articulation that fit perfectly in a flawless performance. That is hardly possible with other instrument libraries such as Kontakt. One switch for one articulation... If you are satisfied with just one version of every articulation, that's alright. But what about the variations on that particular articulation? I refer to the performance articulations in Vienna (e.g. 3 different spiccati, various legatos (slurred, not slurred, fast repetitions...)). I can't imagine all these variations with just one switch. To realize this, you would need almost the entire piano keyboard to provide a single switch for all these minimal differences.