Least we get the benefit of the whole Princess Marco vs Heinous and Rasticore. Actually really dig that plot given it's a lot more laid back than what season 2 has presented us with.
Also, I'm pretty sure I figured out Janna's creep obsession with Marco. To put it simply, Marco is basically some sort of really awkward James Bond. He knows espionage, hand to hand combat, lock picking, and is surprisingly charismatic at times. He's basically a secret agent in the making, even being the right kind of sassy.
With that in mind, it's not weird that sneaky git like Janna would have this autistic fascination with Marco. My guess is she has some assumed future of what Marco's life will be, and is trying to take on the role of the edgy chick who will one day chain him to a motel bed and fuck his brains out, whilst also forcing herself into the chaotic life he's setting up for himself. Marco wouldn't be able to retaliate cause she's got all his dirt.