A site where members actively contribute and play into the existing setting and plot. I feel like lore and plot is often sacrificed in lieu of having super epic character moments or endless socializing between characters. Like, in fantasy-ish roleplays it sometimes feel like everyone is some super special half-demon or angel or god or son of the dragon or comes from some alternate dimension. I'd like to see a shonen rp where factions and the story offer basic shapes that members can mold their own characters into.

That also ties into another point others have already made. A site where you can make accomplished characters right from the start. Not everyone always wants to write a character that is at the start of their journey. And that's less about power, but more about immersion. I COULD write a 50 year old woman who's been places and done stuff, but if I can't give her the skills to back that story up it feels wack. Having a diverse cast is the spice of rice.