The worst things I could see happening is them making DD into some sort of shitty and overdone roguelike and shedding a lot of the RPG systems in favor of super fast paced gameplay. There will likely be some form of progression but it will feel hollow and boring with small boosts to what little stats exist.
I kinda disagree, because that would be a totally different game. While that would be disappointing for sure, it's far from the worst case scenario that I envision (and think is actually the most likely to happen), which is a game that would superflously resemble Dragon's Dogma: nice open world (lolwut?)*, great graphics, cool enemies, cool looking combat, seemingly intricate skill system and character customisation, some kind of pawn system etc., a game that the press and normies (and thus three quartes of the Codex at least) would praise like the second coming of Christ, but that turned out to old fans upon further inspection to be but a shadow of its former self or even worse, a mockery of the original; fewer skills, fewer weapons, fewer armors, fewer consumables and upgrade materials, less freedom, worse combat, more handholding.
*notice how Dragon's Dogma is one of the few 3D action games (or even the only one imo) that managed to get Open World right.
Incline would be taking what they had with DA and expanding on it along with more vocations, more enemies, pretty much more everything that they did right.
And, if you're honest, how likely do you think is that going to be?
Just to drive my point home a couple more examples of what I'm sure will be gutted in some way:
Nights that matter: if there will be dymanic day-/night-cylcle, I doubt the nights will be as dark and threatening, and I doubt there will be different enemies about.
Counterfeiting: while there may be something like the Black Cat, I seriously doubt you'll be able to counterfeit pretty much every single item in the game and the mechanic being as interesting; in Dragon's Dogma you can make forgeries of some quest items, which sometimes allowed you to finish the quest normally, sometimes it would help you finish the quest, but lead to a different outcome. Some forgeries were perfect copies in all aspects, others only in some ways etc. You can pretty much duplicate every single upgrade material, but it always takes a whole day. Some find that tedious, but it's the perfect balancing mechanism, which will be dumbed down for sure: we'll either be unable to counterfeit anything, or not some things like upgrade materials etc., or the whole thing is going to be instantaneous, thus make material farming a thing of the past altogether.
Status effects and remedies: I don't think there will be nearly as many and as interesting status effects, for all of which existed resistances on certain armor parts, and different herbs which served as remedies: petrification, blindness, sleep, torpor... you really think these will be in an action RPG in current year (in the form that DDDA did them)?
Or just one more combat example: You could mount a Drake, Wyvern or whatever, which could then take into the air and make you fall to your death. Sorry, something like that won't return, hope as you may.
Dragon's Dogma was a happy accident, and it will be a long time before we'll get something similar or comparable again, if ever. There's not a single mechanic or system I think will remain intact in a sequel, let alone be improved upon.