BW2 will probably be different, because it's an entirely new dynamic between group. Remember, Dawn will have to level herself out with the whole new group before she and Ash can even begin to develop as a partnership, because the writer's are more interested in the teamwork of the group, not romance. Though, that being said, she looks as if she'll fit in with Cilan and Iris fairly quickly, based on both preview and what the actual anime has done with such meetings before. If I remember correctly, which I think I do, May was accepted quickly by Dawn and the group, so I feel it shouldn't be any different for Dawn returning. So hopefully it won't be too long before Ash and Dawn are getting nice, preferabley solid hints.