Spoilers...
I agree mostly. Jenna does get quite a bit more favoritism in her route, but there's also themes to take into consideration. Jenna's character arc is basically her achieving self-awareness and empathy. She projects her own faults onto others, especially Heather who she calls the "eternal victim," until Chase provides counterpoints to her views. Leo on the other hand is a tragic love story that only has tragic endings which, in my opinion, is perfectly fine. He was driven mad by through a feedback loop of Echo and his love for Chase. This is rectified in other routes like in Jenna's where he snaps out of his delusions and in TJ's where he kind of ghosts Chase after seeing that he's not interested and seems to handle it pretty well without the hysteria driving him insane. He's a perfectly reasonable guy outside of the town's influences.
I definitely do see the favoritism though. I think sometime after people criticized Jenna for being obnoxious some of her lines were rewritten to be less grating and more understanding of the player character. One was even inserted to compare her to another female character who was really likeable, though that was probably a throwback.