Each set of games seems to bring something new to breeding. Aside from changes made in between generations, such as the glorious new fate of the Destiny Knot, egg shells no longer being worth any experience points, Masuda, and of course, the allowance of incest in the name of finding the perfect specimen, each followup to the core games since Gen III has introduced something new:
- Emerald gave new utility to the Everstone, Flame Body and Magma Armor, the Light Ball, and even changed the layout of Route 117 to more easily accommodate breeding, and therefore set the trend of long expanses of land to travel across being placed directly in front of any given Day Care Center.
- Platinum introduced the Power Items to breeders.
- Both Emerald and Platinum made minor tweaks to the way IVs were passed.
- BW2 improved the chances of inheriting abilities, and set the nature that the Everstone passes.
The remakes, on the other hand, tend to follow the mechanics set by the games that precede them; FRLG didn't introduce anything new (although they're the worst games to breed in, anyway), and HGSS gave new egg moves to almost everything. Because of this, I doubt that we'll really see anything really game changing until Z/XY2, and I get the feeling that finding egg moves in the wild will be the change that we'll see with ORAS.