An architecture limiting the number of articulations to the number of MIDI channeles -- 16 -- would seem vintage-synthy to me. Limiting timbres to 16 made sense in 1983 when MIDI was designed, but not anymore.
On the contary, a virtual instrument without these capabilties is what is similar to non-multitimbral vintage synths. And it makes perfect sense to have these capabilties in this modern day and age... especially when needing to access articulations by MIDI channel within a score.
If the Vienna Instrument player had multitimbral capabilties the benefit of using it within VE Pro would be even more beneficial, as each instance could hold a multitude of articulations and circumvent the 16/32 MIDI channel limit by adding more instances (as I do now with multitimbral VI's.).
Nonetheless, I understand that the Vienna Instrument Player does not have this capability and thus remain very dissapointed.