I have been always wondering..
 
If i want to automate some parameter of certain vst with external midi controller,
 
I have to use atc. but it is a very annoying, and buggy thing.
 
On the other hand, If I set that certain vst to 'configured as a synth', then I can use midi learn, and automation can be done easily.
 
I use izotope's stutter and Nectar (harmony module with midi note input) this way.
 
it means, I should turn the stutter(or nectar or anything i want to use with midi note) into a synth.
 
This is terrible because my plugin list will be messed up.
 
Why VST (not vsti) can not accept the midi signal by default?
 
Is there a way to go?
 
Best,
SOHN.

There is no need to configure FX plug-ins as synths. Starting with X3 the VST2/3 drop down in the VST standard header for plug-ins has an option to Enable MIDI  Input and Output. Once MIDI input is enabled for the plug-in, it will be available as an output for a MIDI track.

Wow.. I am a long time sonar user, and.. How silly i am!! 
 
It is great to ask here! It is Veeeery good to know!! 
 
Thanks a lot!