It might be due to the fact that the OP up to now was used to libraries with no legato transitions, hence, the midi-channel system had been a very conveniant way. At first glance this workflow could be transferred to VE, but you won't get legato transitions between different instances. Thatswhy this would only work, when only simple patches without performance algorithms would be used. As those are a main feature of VSL this approach is not working to the library's full extent.
Well, the VSL team could however implement midi channel information as another source for X/Y-axis-patch selection in the VI player. Of course, this would only work, if the VIs are loaded directly into the DAW. I guess, it would not be a very difficult task for the software engineers, so, I would appreciate this as another option.