Anime-wise, I'd like both to be focused, but I'm leaning a little somewhat more towards Hikari. Because well, game adaption-wise, she's supposed to be there. Face it, just because they recolor Red's FR/LG clothes by adding some color from Kouki's clothes and putting it on him doesn't change the fact that's it's still Red's clothes. You know where I'm getting at. Satoshi's game icon hasn't been in the "game" since G/S/C (there, he wasn't even the main protagonist anymore) and if the anime were more faithful to the set of games it's based on, then they would've ended Satoshi's journey somewhere in Kanto/the Orange Islands and made a 3 year gap, making Kenta the main character. Yes, he's named after the creator of Pokemon, but during the G/S/C games, "Red" seemed like a legend in those set of games. A character named after the creator, being a "legend" seems fitting to me (besides, think of the badass cameos :0). Besides, it makes me sad how dragged out his journey is. :,|
Well, that mini-rant aside, yes I want the Diamond and Pearl anime to revolve around both of them (seeing as they added Hikari into that text with Satoshi that introduces the Pokemon anime in the opening, which they never did for Haruka. Makes me think they'll treat her as a main character, the same "level" of main character as Satoshi). Though it being revolved around Hikari and Kouki seems more fitting, in my opinion. *shrugs*
And yeah...spoilers.