D&D is epic fantasy, with options for other different subgenres, but the game is not designed to be a loyal adaptation of classic superheroes. The age of classic superheroes where a lazy scrippter could use the superpowers like a magic top-hat to resolver all the challenges has ended time ago. Now we are in the videogame age, where the main characters, the PCs, are designed for a balance between power and vulnerability, success and failure. Today the old superheroes who could move buildings are too boring and "Mary-Sue" for the eyes of the new generations. My opinion is the famous superheroes we know are going to be "nerfed" for an easier adaptation to future videogames. There are videogames of Batman or Spiderman, because the are powerful but also enough vulnerable, but Superman is too powerful.
The future setting of Witchlight could allow crossovers with mash-up versions of famous franchises for children, for example a domain about sentient ponies, or other ruled by the archfey the princess Peach who summons the heroe Mario against the hordes of the king tortle Bowser.
We will see more crossovers because they are valious by speculators, something like "limited editions", and as hook for the fandom of the other brand. And players do a lot of mash-up+crossovers in their own tabletop. Castle Greyhawk is an oficial example of parodic crossover, and maybe this "place" could come back as a domain of delight for "Witchlight".
The current Ravenloft setting allows dark domains with XX and XXI century technology, and this could do possible famous horror characters as "guests". Maybe the dark lord is a survivor who betrayed others, and his punishment is to be haunted by a "clone" of that slasher. Didn't you want?, then enjoy two cups! Or a mash-ap version of Scooby-doo appearing in Odiare, the domain by Maligno, the evil carrionete. Ravenloft can be a very grimm place, but also allowing softer stories like R.L.Stine "Goosebumps".
Other option could be a "fake crossovers", something like a sub-plot within the main story, where a group of characters play their own version of Dragonlance (with a different list of characters, for example, or Tas as a girl). Here shouldn't worry about the canon.
Not even Hasbro can totally sure about their future plans. Maybe Paramount wants to continue the partnership deal with Hasbro, but Disney shows a better offert, or there is a future change in the main chairs from Hollywood for the next year, and some agremeents should be renegotiated again. Or some videogame studio goes bad and then it would be acquired by Hasbro for their franchises, even if these were relatively old.
Hasbro needs a good relation with the different cinema studios, but these are rival among them, and they wishs exclusive rights.