I have added this comment to previous such requests:
It would be helpful if Steinberg would expand the macro system so that we can pass arguments along with the actual command.
Then we could make a macro: Create Instrument Track (Plugin, MIDI-In, Audio-Out, Event Type, Name)
A PLE no. I usually do it using one of the following two ways:
By sending sequences of MCU commands (This can be useful for both instrument and fx plugins) and
Properly setting up vstPresets and then having a macro for first opening the appropriate window, (Track Preset: Open Browser, when I want to replace the instrument and Using Track Preset… when I want to insert as a new track) and secondly feeding the search box with the name of the preset I made. This obviously needs an external utility to type in the letters, I use one made up by me, but AutoHotKeys, Bome MIDI Translator Pro and other can do it. As @Johnny_Monteo it would be far better and straight forward if there were user assignable arguments. Not sure of how complex this would be though.