Oh man, somehow I had never even considered Strex Corp drugging everyone as an explanation for Kevin's peppy attitude, but it makes so much sense. I almost...feel bad for Kevin now, as terrifying as he is. They really do need to do more with Desert Bluffs, maybe have Strex Corp start expanding or something sinister like that.
Honestly, they can't introduce a character like Kevin--even giving him his own parallel episode--and then not bring him back. The fans would riot. We definitely have to see him and Desert Bluffs again.