The Magicians was a brilliant show that ran for five seasons and was critically acclaimed. Nancy Drew, while not to my personal tastes, ran for four seasons, making it more successful than the vast majority of television series.
And prior experience with producing science fiction is not necessary, because writers can adapt to new subject matters. Michael Piller started out on Simon & Simon and Miami Vice, and only produced two short-lived science fiction flops before he got the showrunner gig on TNG and became its most acclaimed writer-producer. Ira Steven Behr's only significant producing credit before Trek was Fame. And while we're at it, Star Trek was Gene Roddenberry's first science fiction series, after a career working mainly on Westerns and cop shows, with his only previous showrunner gig being the Marine Corps drama The Lieutenant. Noga Landau has considerably more showrunning experience today than Roddenberry had in 1966.
Of course Kurtzman's involved. He's the big boss, so he has the final say on every script and every creative decision, even if he's not the day-to-day showrunner. This isn't a matter of binaries, either someone's involved or they aren't. It's a team effort and everyone on the team is a contributor, even if some are more involved than others.
