Well, difficulty isn't everything. If the greatest point of difficulty in the game is playing Hell or Hell, where you have to avoid getting hit a single time while taking out the smartest, most aggressive enemy waves, there being leeway on a lower difficulty is kind of moot. Similarly, the Style grading isn't everything either. People complained about DmC's but it's a barely-working grading system anyway, all it does is give you greater rewards for remembering you have more than three moves; plus, it stops mattering once you unlock everything anyway. Do you need a video game to tell you you're a good boi? DmC is largely easier in some ways because the enemies have more broadcast, but DMC4(se) still felt right in line with the series difficulty, for the most part. However, DMC4 (and then se) probably feels easier because the gameplay was developed for roughly 20% of the roster, mot of that roster coming way after the enemy development - but think about what they can do by creating enemy waves and gameplay specifically for characters who they know are going to be in any particular situation.
I'd have faith in them being able to make V, and anyone else's scenarios to feel specifically theirs now that they're making them all at the same time, rather than the hodgepodge that DMC4 ended up as. It's possible that V's playstyle isn't all that different from a normal character, and it's just a matter of how summoned demons might even be used. They could end up being just like any kind of weapon, where V plays like Yuna in Dissidia 012 - all the attacks come from demons appearing and doing an action, say, a launcher, but V and the summon have their own hitboxes, and perhaps while you feel like V might be more safe, if his summoned demon is struck, you can't use it for a moment or something. So you could strategically use demons to protect V, or you otherwise have to account for having weapons that can be disabled for a time.
I think what ultimately matters most is that they can solidly divide the levels of skill in the different difficulties, rather than simply "this guy hits a little harder on the next step up." This franchise desperately needs to get away from the elitist, "dis is da hurdest!" mentality so that it can stop being so niche - there's a huge reason why we only got newer installments so much later. There's nothing wrong with the barrier of entry being low enough for anyone to get into it, and to want to have fun, but let Easy be easy, and let Hard feel like you really do need to improve, aaaand probably don't call the easy mode Easy, because people seem to get all uppity about the implication of playing on lower difficulties (case in point, really).