Wow ... I've finally had the opportunity to play him, and it's amazing. DJC is not needed. In the air, I had amazing priority. All the aerial attacks have reduced lag, so I could do more of them per jump, and I always felt like I had an extra jump and an extra aerial attack to use. I was able to play Ness just like I did in Melee--minus DJC--except that EVERYTHING WORKED BETTER. I think the adjustment for Ness mains from Melee will come pretty naturally. I'm really happy with both Ness and Lucas in this game.
*wuvs them*
EDIT: Oops, seems I posted this in the Lucas thread. I was talking mostly about Ness above. Lucas's moves in the air seem much faster than Ness's, and I still feel the same about not needing DJC. I'm overall better with Lucas. The only problem I seem to have with Lucas is finding good killing moves.