My own forecast is:
We will see the remake of the module House on the Gryphon Hill, and maybe later the six modules about the grand conjunction in one book. The next step would be more modules set in some island of the terror.
If there are some project about anime or action-live adaptation the producers could ask some story set in modern age. Or scripters could force some change in the metaplot.
We have to remember the gothic Earth from "Masque of the Red Death" is canon in D&D multiverse, because Maligno, the marionette lord of Odiare is from Italy. (I have imagined sometime this lord creating a squad of doll half-golems) If there is an official crossover between Ravenloft and Gothic Earth we should be really careful about some matters. Maybe in my own gothic Earth cursed monsters can go to water sources in Lourdes to be healed, and if I am the DM this works, and "Blood Mary" was a vampire-hunter heroine who tried to save her land against secret lodges ruled by vampire clans.
The shadowfell domains were canon in 4th. There weren't really within the demiplane of the dread, but they could be useful for softer stories of gothic horror. Let's imagine Shadow domains ruled by fiendish or catastrophic dragons.
* Would you allow abyssal genasis in Ravenloft?
* Grand Caliph Muhdar ab Sang (or his heir), enemy of the empire of the Avonleigh (in a region from the material plane) and Diamabel, darklord of Pharazia are potential great antagonists, at least the type of villains I would like them to be kicked-ass by my own PCs. I like the idea of Diamabel's followers as people who try to be good, merciful and just, almost innocent, somebody you would be friend, but they don't notice "trees are known by their fruits".
* Para-elementals in Ravenloft (mist, blood, pyre and grave) and half-para-elementals could be a surprise to PCs too used to slaying undeads.
* The cult of Elder Elemental Eye could be an interesting antagonist faction in Ravenloft, a place with enough madness and nihilism (and cultists with para-elemental symbiont grafts) Obyrith cults also could be a challenge for PCs and even for Darklords.
Vladantilan, land of vampyres (living bloodsuckers) and homeworld in the material plane of Vladimir Ludzig, would be a nice place for a zombie apocalypse or something like this. Ravenloft needs new space a sandbox to be "destroyed" by fan creators, where they can add their freakiest ideas but without losing the main essence of the setting, a dark fantasy where monsters reject opportunities for their redemption and they suffer poetic justice by the dark powers. Ravenloft can't be only hunting the monster of the week or a "
pest control" as Resident Evil 5. It isn't only a night king controlling hordes of undeads but about because they are punished with a curse, usually with poetic justice.
Ravenloft needs stories about influence by the dark powers in some regions of the material plane, as poisonous rewards. For example a group of heroes after killing a tyrant they are sent to an unknown region of the material plane, to find that land is rules by other tyrant, and they have to start a rebellion again. If the tyrant is overthrown, it will be after years of fight and suffering, almost a pyrrhic victory.