Wow, I don't remember the part about stimuli, but that kind of gives the idea some credence, apart from the way he views humans. Very interesting idea.
Although, it does present some problems. It would mean that Reckoners would have to take place in the Cytoverse, which also involves Earth. And you'd think that they would mention extraterrestrial life or cytonic abilities in Reckoners if that were the case, or the event of Calamity and people with superpowers in Skyward. Also, of course, why doesn't Calamity appear in traditional delver form.
But very interesting idea. I bet Sanderson based his concept of delvers off of Calamity.