Seriously? Well, GF creates some really great features that they just seem to abandon in the very next games that they release. Super-Training, Triple and Rotation battles, DexNav, the streamlined PSS system, and Megas Evolution are some of the things they either outright abandoned or pruned in SM that should have been permanent features in all future games using their original incarnations as a base.
This is the series' biggest problem imo. With most sequels to other game series, I feel there's a definite upwards trend of gameplay refinement. For the last three generations of Pokemon, I wonder which aspects of gameplay have become more or less cumbersome with each new set of games. It feels frustratingly random desu.