- Everyone is right about EXP Share. It has been expanded since Gen II and now affects the entire party. I left it on the entire game and by the end I had three maxed out party members and my HM slave, who had never once been in a battle, was in its early 80s.
- Amie has no effect outside of single player besides being cute and collecting cute furniture. In battle, the more doted upon your guys are, the more likely they are to shrug off status effects, land critical hits, dodge attacks, etc. Super Training is EV training and fully training someone can provide small stat boosts. It's largely negligible in single player, but par for the course in competitive multiplayer where a difference of a couple points can mean victory or defeat. Also it's kinda fun to do the secret challenges.
- Breeding hasn't changed a whole lot. You can now get egg moves (where known attacks are passed down from parent to baby) from both the dad and mom.