The idea of turning Pokemon Rejuvenation into a full-fledged original IP has actually been brought up in Jan's tumblr before and Jan did consider it before (though it's in a pretty old ask).
At first I was wary of that idea, since pokemon was the reason I played Rejuvenation in first place (not that I don't love it's story and characters, mind you! Just that they were a pleasant bonus for me rather than the reason to start the game for me) and I loved the aevian forms, pokemon battles, having a pokemon team and more there, so I didn't like the idea of it being a original IP.
But after reading that post, I can say I've warmed up to the idea of turning Rejuvenation into a original rpg, I wouldn't actually mind that.