Whole iconic debate is stupid and mostly related to people who, for some reason just hate when somebody mentions that they like original Dante.
Why it's stupid? Because there is some characters who was completely based upon other characters and yet they are still iconic.
The inanity of the idea, though, is that people who denounce DmC consistently use the "it ripped off X" as grounds for criticism.
I'm not aiming this at you mind you, I'm just commenting on something broader based on what you mentioned.
Kamiya said long ago that he took inspiration from Space Adventure Cobra for Dante (or at the time Tony Redgrave)'s design and personality, because Cobra was iconic and something he loved. He didn't quite rip off Vash the Stampede, nor InuYasha - although InuYasha and DMC3 have striking similarities with their brothers' quarrel, but it's not like that's new. If you look at the concept art for DMC1, just before they made his jacket into a trenchcoat, he looked almost exactly like he jumped outta Space Adventure Cobra - the only thing missing was a cigar.
Dante's design looking "ripped off" from other anime heroes is simply because, honestly, Japan loves to f#cking copy itself and milk a concept to death (seriously, they find what's profitable and do that until it isn't, and oftentimes the quality goes down drastically because they bank solely on concept, and not the content) - case in point, most shonen heroes will have the same personality, and wear a lot of red, because red is a heroic color symbolizing power and confidence. Red is the leader's color.
What bugs me is "Kamiya took inspiration from Space Adventure Cobra" is fine, but "Tameem took inspiration from They Live" is not. It's a completely retarded double-standard.
For example Nero is basically looks like younger version of Dante, yet he is not iconic, because he lacks same recognition grade as Dante.
The lack of recognition is mostly due to Nero only being in one game, whereas Dante was the one that carried the franchise as far as it did. Now I'm wondering if Dante hadn't been in DMC4 if Nero actually would have been more recognizable...