You are never going to have a scale of jump like you did with DMC3.
I disagree.
Think a little outside of the mechanics and weapons that you have with your character. Other than those stuff, how much have action games (especially DMC) really used the other parts of their games to serve their gameplay/action?
When you start a game almost always the first thing that you notice is the environment that you are in, yet barley any action game really uses and treats that aspect of their game as a part of their action. DmC did tried to add some stuff like trains and damaging enemies with acid, but I think you can still do much more than that. They can make the environments and your placement in each of them, part of their gameplay/combat system. I'm not talking about environmental finishers and stuff like that, but actual moves and abilities that you can use based on whether you and enemy are close to a wall or near a pillar, etc. Or having environmental effects, like you are fighting in a wet environment then if you use a weapon that generates electricity then you can see different reaction/affects on enemies and set them up for combos/attacks in a unique way that you couldn't necessarily do in a dry environment.
The same goes for other things like AI, or enemy physics.
There are lots of things about games that we've just come to agree on how they should work, because we've barley seen any developer do anything new with them or approach them from a different perspective. An example of this would be how you approach enemies in RPGs. Before Dragon's Dogma, I had never even thought about climbing on enemies and then having them fly away while you are still on them and mercilessly stabbing their wings in hope of having them fall down. That thought had not occurred to me before, cause I had grown accustomed to the traditional way of approaching enemies in that genre. So that's why when it first happened in DD I was like "Oh, SHIT! Is this really happening!?"
And I think the same kind of things can happen in action games where devs could use parts of the game like environments, like general physics of enemies etc, to make you approach the action in a way that you haven't thought about before. I know doing these stuff and coming up with genre defining ideas is not even remotely easy and good ideas on paper might cost a ton of time and resources and even then lead to very very annoying and poor mechanics in the actual game. So I know it's very tough, but I still think believe that achieving these things are possible.
Now to be clear, I wouldn't be mad about DMC5 if it didn't have these genre defining things. You are not gonna find me say "Oh, DMC5 sucks cause it doesn't use its environments as parts of its battle system." But I know that someday, some developer will be able to do this and I'll be really excited about it.
That being said, I would be disappointed in DMC5 if it didn't make me go "Hah, that's cool. That's new. I haven't seen this mechanic before /or thought about using it in this way in other action games".