You are right. And thank you for making me think about it. The more I think about it, the more I think we can be ambitious with the movie. It shouldn't really be about the dangers of of individual Rhampires. Not primarily at least. Because they basically share the same ones as Blampires do. Well, the movie / media should have those, of course - if only for graphical reasons.
But there's another unique layer we can play with, and an indirect route to crippling the strategic political power of Red Court. To break them long-term, like Black Court was broken. Specifically, I am talking about half reds and those addicted to rhampire saliva. Those are unique mechanisms of control that red court is using to recruit people, and to control people and institutions. If we can deprive Red Court of their unwilling mortal slaves, we can do a lot of good strategically. So:
1) Have the movie demonstrate that the Rhampire produced from the mortal is not the mortal itself - this would decrease the number of people willing to go from half-red to full-on Rhampire willingly
2) Demonstrate that the addiction can be fought and controlled. If there are any rituals normal people can do to help with the addiction (not half-red state, the addiction), include and encode those. This cripples or at least combats the networks of influence rhampires have among mortals. We might have to develop something there, some manner of common person magic / ritual / faith invocation maybe to help with it.
3) Encode Mercy In Servitude into the movie as a way for half-reds to get control over their hunger and avoid becoming full on rhampires. This is straight up a trick from Age of Legends, where a Solar developed a language which had prayer to their name encoded in it as part of everyday speech in order to farm cult-generated motes. Something along those lines could probably be done here. And it can be done in a movie - have the half-red hero, for example, find an ancient tome describing a simple ritualistic offering to "Radiant Pearl of Sorcery Pure and Impure", where they enter a pact, promising to follow X precepts and in exchange the ancient goddess grants them control over their curse, though not the freedom from it, not until the last vampire is dust in the wind.
Actually, yeah, this works. Have the main hero end up as a half-red at some point of the movie, enslaved by their rhampire master. Pit of Despair and all. Have them get in contact with the resistance (heavily coded to be Fellowship of St. Giles or White Council), look for cure and methods to combat their curse. In the end they discover the ritual described above, perform it, which grants them power over their hunger and strength enough to kill their sire (a young rhampire). Cut to sequel / TV show as the half-red paladin (because yes, the ritual in question would basically be a paladin's oath) of the Radiant Pearl explores the supernatural world, fighting evil.
In the next movies / establishments in the franshise we could do stuff with Prayer Eating, possibly, and soul trade, both the warnings of, and getting people to trade with us, instead of hells.
Yes, I really like this idea in general.
Also, such a movie in general could be a gateway to a series of media products, all meant to slowly prepare the world for the lifting of the masquerade.