They would have used it as a testing ground for the new version or familiarise people with it or at least be an alternate costume, they are using Jill's RE5 outfit although her RE1 or RE3 are more famous.
They know they blew it with this one, thats why we are not seeing or hearing anything about this emo since the his debut 5 months ago
This. MvC3 would've been the perfect time to try and ram the new "Donte" down people's throats, however, they saw the reaction from the DmC trailer and were like "oh ****".
Emo girls want to kiss emo boys, but emo boys just want to kiss other emo boys. - Gamerkyle
I figure it is because they started working on it earlier before the NT Donte was set and did not know where that was going and it was created by another division of Capcom and not enough communication. I also guess that it was created by another division of Capcom that seems to like and know that fans like Dante.