I've never finished my Diamond nor Platinum. Too ****ing slow and too ****ing boring. Spent 150+ hours on HG, though - only thanks to it I was able to appreciate new abilities for Pokemon and Phys/Spec split.
I'd say Platinum's worse than DP since they changed the female main character's sexy outfit to a stupid-looking one.
. . . I don't even. What. Yeah, how dare they make a female character's outfit suit the colder climate at the expense of it's sex appeal. And it's not like said character is a young teenager or anything, no.