[mod edit] No need for cross posting. Please delete your original post next time before doing so.
The VST3 is a good evolution with a lot of underused features, the per note control is a killing feature, sample-accurate automation, audio in VSTi, and the new routing capabilities.
And i want to talk about this last aspect, actually a VST3 plugin will operate on 2 channels for stereo, 6 channels for 5.1, but i think that a big limitation ( particulary in Cubase or Nuendo ), is that it’s impossible, to select or deselect individual processed channels, it’s all the channels or nothing.
I’m not quite sure, maybe it’s a per plugin routing code, or if the VST3 is like that and couldn’t be tweaked.
A nice and open way could be to for example, able to select the number of inputs and outputs of the plugin ( for example a spectrum spliter ) in real time, then on the next plugin slot, 6 inputs, the 2 first ( bass part ) goes thru, and the next 4 are treated within an effect, settings appliable in the little routing view of the plugin slot ( this thing always make me think that this routing snapshot could be really powerfull, but now it’s more like a visual helper with very limited interaction ).
Oh and yes, it does the job well, and it work like it have to, but sometimes, i’m dreaming about changing a track channels number on the fly, i cannot transform a stereo channel in a 4 channels track… You have to select the channel number at the track creation. Or mutable tracks, like a temporary 6 channels routing chain, with a little VST3 channel mixer insert before the fader, on a stereo track. And with the all new fresh 8 free slots, with this feature, a track can became a true christmas tree 
but one unique, very powerfull, flexible, and near limitless feature 