They didn't really add too much if you think about it. Some are just pre-evolutions and evolutions of classics (Eevee, Chansey, Mr. Mime, Electabuzz, etc.), and the newer ones aren't the best things to ever come out of the different generations either. :P

But back to the secret: What kind of points are different? I just bought Diamond since I liked Dialga more than Palkia. ^^;