That's part of it but another part is how people felt about Nero. To a lot of people, he wasn't what the series needed or what fans wanted at the time.
Nero too. I was there when the backlash happened. There is also the whole DMC4 & RE5 are no longer PS3 exclusives fiasco. I remember many a rages on video game sites and forums. Funny enough, it's was what convinced me to get a X360.
Its not like the dev team had their dev time cut short and thus had to rush out a product which resulted in them dropping a lot of their more ambitious ideas they initially had (some ideas that they seem to be reusing for DMC5). Nope somehow the fact this is the first HD DMC game (although I can see how that could become a problem with development costs and all) and Dante not being the main character is somehow the root of DMC4's problems.
When I look at the what was kept on the cutting room floor, I do sigh a little. Had Capcom gave Itsuno and his team more time, the levels and story could have been better fleshed out.
Also, I would have preferred Nero's prototype design as a Sherlock Holmes style character. I actually remember a friend in high school who found leaked sketches of Nero and he would do practice drawings of the prototype design.
I like Nero, but when you think about it, he's Gene (from God Hand) combined with Ichigo Kurasaki, and essences of Dante and Vergil.