Honestly, I get sick of people not wanting to listen when I have a good argument on why DmC is underrated. I'm not at all calling it the best, but this is something that the haters should take note of. I'm going to cover certain topics of the game one-by-one, covering things that got the most hate, things that didn't get too much hate but are worth going over, and things that probably deserved more hate. I will be adding TL;DR's for any of the sections that get to be long. If you have something to add, please do so. Maybe I'll understand the hate a bit better and can decide if I want to formulate a better argument or want change sides for any of these.
Dante: He aesthetically looks different. Okay, that's not a big deal in a reboot as long as they keep the core character the same, which for the most part they did (I have one minor issue I'll go over later). Basically, this'll be a comparison of both Dantes to notice the similarities and differences, and see which differences are justified. First, I'll look at their pasts. Old Dante was there the day his mother was killed by Demons and was separated from his brother. Alright, that sucks, but that's not "watch your mother get her heart ripped out and be abused by Demons in an orphanage" level of suckiness. Not saying that Old Dante didn't have a traumatic past, but New Dante had a more traumatic past. Alright. That just gives New Dante justification for hating Demons, among other things. Old Dante in DMC 3 (since this is the Dante that New Dante based on) was quite cocky, had some witty lines, and was a total trickster. New Dante was a bit more cocky (to a point bordering on douche for some), also had some witty lines (overshadowed by the fuck you battle in the demo), and was also a total trickster. New Dante did sometimes appear to be a douche, like hitting on Kat too much or hitting the can out of the guy's hand in one scene. Although once he heard Kat's story, he stopped. With the can he knocked on the ground, he knew how bad the stuff was, and a real douche wouldn't care for a human drinking poison. Now people might judge his lifestyle at the beginning to be a sign of douchiness, but if you remember the moments when he is more sincere about his past and have a basic understanding of psychology, you'll know that there is a good reason for this. If you play through the whole story and pay close enough attention to Dante, you can also see that he develops more to actually care for humans, whereas before he was mostly indifferent to humans (only because he didn't exactly have the time to care for or have a connection to them). In DMC 3, you can see Dante always having that sense of justice and care for humans, but becoming wiser and less arrogant throughout the game. However, Dante already had a care for humans due to having a human mother and meeting Enzo, so he didn't need the development. Speaking of Dante's mother, that's the one complaint I have about New Dante is that his mother being an Angel takes away one of the themes of the original series; humans can be stronger than Demons. This is a fault with the story though, and not with Dante himself, but it's still worth noting.
Dante TL;DR: New Dante is the same as Old Dante at the core, with just a different background and aesthetic, causing the character to be edgier, but within reason. (Edginess is okay if there is good justification for it.)
Difficulty: Yeah, it is easier, but there are two reasons for this: 1. The combat flows better, and better flow makes things easier for the player, so honestly this is a good reason for the series to be easier. 2. Do you see how whiny people can get about games being difficult? To be honest, this is a mixture of a gaming community problem (some people wanting easy games, some wanting hard games) and a marketing problem (the main people trying this game were DMC fans), and is forgivable, but shame-worthy.
Vergil: Vergil's betrayal was kinda predictable if you think about it, given what we knew about him from before and the actions we've seen him take. You can guess that he doesn't have much care for humans in the first place, and honestly I kinda wish they could have done things differently with him. However, I guess his ego is just the sad effect of him being raised by rich people probably telling him he's so great and all that shit. Although when he goes through the events of Vergil's Downfall, he does develop into a different character, who starts to accept that in the end he is power hungry. There are some good things to note about Vergil that they did differently though. He does truly care for his brother (before the DLC) and also feels betrayed due when Dante refuses to rule with him (which is also a sign of his ego, but is still noteworthy). He also seemed to emphasize the calm and collectedness traits of Vergil, then the power loving traits toward the end. If DmC got a sequel, I could probably defend him better, but right now he doesn't deserve much.
Vergil TL;DR: He's somewhere in the middle as a good or bad character.
That Whole "Conspiracy Theory" Kinda Story: Yeah. I'm not defending this much. It's honestly kinda cliche and not something that I find worthy of defending. Although given that the game was a reboot, I guess it's allowed to try other things, and it honestly didn't do a horrible job (although it wasn't a good job either). I'm not saying that the story itself is bad, but this KIND of story is bad.
Mundus: Mundus is not really something I'm going to say is good or bad here. As part of the above section, he at least fits well and makes that kind of story not horrible. In DMC he's honestly a bit underdeveloped as an antagonist, but that was in 2001 so it's whatever. He does still act cliche at times though, bringing Mundus closer to a meh.
Bosses: Yeah. No defending this. Half the bosses seemed to have the same strategy.
Vergil's Downfall: Let's be honest; this doesn't deserve much either. It was a lazy cash grab for the most part. The cutscenes were just drawings, the boss was just Vergil with a little extra, they could have actually given Yamato different forms, and I'm certain they re-used environments (some of which make sense to use though). The one good thing is that this showed us what did happen to Vergil after the ending and helps set up for a sequel.