I may be wrong about this as I am not a huge DMC fan...
But wasn't the general opinion after DMC4 that, gameplay differences aside, as a character Dante was far more fun to play as, due to his personality being geared towards just that; having fun?
And the response to that is making another new character, but calling him Dante? As if it were the name of the character that was the important thing?
At least Dante seems to have a weapon that can emulate Nero's arm now, so he does not need to come back.