I do not claim it is not possible to send MIDI to external gear or that is not useful, sorry if my statement could be interpreted that way. Reaktor is for sure very powerful DSP performer and can send the output of some processing to (MIDI) output.
It is just so then when you want control something and have 2 possibilities, one with scripting and another not, the first solution in general wins. That has an explanation in related theory (for controlling systems), but I do not think that is a good time and place to discuss that

Practical consequence of that in music is for example unavoidably huge number of panels, knobs and switches in softsynths, including Reactor.
I do not even claim that Reaktor can not do what Robert wants, probably it can. But what I need requires scripting...
If Reaktor can parse arbitrary SysEx and somehow communicate with outside world without MIDI, I am ready to agree that I am wrong about it. I just got an impression it is more to use / modify / create its own "virtual hardware" then for operating fixed external one.