I havent finished the main story yet, But, while it was slow to start, I am noticing judging based on the town map that there is a lot more content than the last go-arounds. I'm about to beat the ground gym (#5). I definitely don't play Pokemon for the story, but this time around I seem to be a lot more interested. The added moral dilemma makes the bad guys actually interesting for a change. On the other hand, there's still enough room for that moral dilemma to come out all crap with sprinkles and rainbows. It's still got that formula though. Perhaps other Pokemon fans have been so groomed on it's traditions they won't take much change. I like enough of the new mons to be sad about not being able to have all of them on my team. IMO, gen 3 was the worst in the series. Im not far enough along to compare it to the others.
I played through, transfered my mons from Platinum, and did some of the White Forrest/Black City stuff. The game definitely has a lot of content, I'll say it again best in the series hands down, just wish it was as big as HG/SS.