Honestly I think the treatment done to Vergil is way worse than to Dante. He went from a focused, DETERMINED and upright rival to just being...kinda there...and kind of a wimp.
I don't have that much of a bone to pick with new Dante/Donte. But I'm glad to see him gone tho. He had a few good or chuckle worthy moments but nothing that stuck
Old Dante was frankly ridiculous and silly, but it was kind of part of the jest. The world of devil may cry was always kinda colourful as it was violent and he kinda fit that mould. He revelled in the over the top without taking himself too seriously (at least in 3 and 4 which are people's favourite if I can recall). When they tried to make him more serious, aka DMC2, people didn't like it either. So it's not like you're seeing a first OP.
The problem with new dante is that it seems so much like adults trying to be edgy teens and serious in a story about a half-demon half angel fighting giant Bill O'Reilly heads. He was basically at the image of the cliche "anti establishment" plot: sloppy, slurring his lines, often witless when it came to dialogue that took itself more seriously that it should've. I can see the angle they were going for tho but it just felt like they were trying way too much to appeal to a pre-conceived notion of what the demographic for these games were. He was just "some sassy/cocky asshole with short dark hair and an attitude", like many other gaming protags that came out at that time except this time WITH SCREAMO
Didn't help that there was a plethora of things outside of Dante's design that didn't sit well with the fans as well at the same time, making the hatred more visceral. People hated him not only because of his looks but mostly because of what he represented.
Again, I don't think he's as bad as new Vergil, but I don't see him as particularily good either
Imma quote Coffee Dog actually because he summarized it super well
Dante went from being in on the joke to being the joke itself.