I don't think so either as it's not really anything new but I know how some people are.
I think of the Grimms as kinda like the Slayers in the Buffy universe. They have "gifted" physical abilities but if they don't train them and accept them they don't do a whole lot. Another analogy might be "super soldier" ala Captain America. Basically the best a human can achieve.
The way they are building the mythology reminds be very much of season 2 Buffy. I think getting renewed so early really gave the writers the freedom to explore the wider universe vs. worrying if they needed to wrap things up if they didn't get renewed.