>>44991562Because Reshiram stands for half-truths, not absolute ones. N was raised on the half-truths that Pokemon suffer, Ghetsis showing him that only perspective in life. Team Plasma in general spouts half-truths as they claim to liberate Pokemon in order to protect them. Reshiram is one half of the original Unova dragon, which means not the full picture, and hence again, a half truth of what it was actually like.
Hilda/Hilbert being paired with Zekrom is meant to counter this viewpoint by giving the whole picture. They aren't meant to stand alone as some ideologue; but one could say that they idea of Pokemon/people working towards a bright future together rather than apart actually IS idealistic, and perhaps a lot of people on this board just don't get that.
It's not just aesthetics, even theme wise it fits and I played the Black versions of Unova.