I think it's pretty obvious that it will be implemented. When Yu-Gi-Oh switched to 3D models in their games, that's when they added customization. It's a lot easier to have customization with 3D models than sprites. The only question in my head is the extent of which it will go. It will probably be limited to clothing, and accessories, due to the fact most games have a canon head characters.
Yeah, I remember when games like Animal Crossing: Wild World introduced hats and eye-wear, and soon with Animal Crossing: New Leaf having Shoes and other accessories.
Because of the 3D in newer games... has given developers the opportunity to bring in more unique features. And yeah, I do think Pokémon X and Pokémon Y would be limited to hats, clothing, shoes and many different accessories.
They could also give the player options on where to put the eye-wear as well, seeing as we've seen the sunglasses on the player's hat in the trailer. ;)
Oh talking of eye-wear, I wonder if we can wear makeup if we do indeed have customisation. I mean much like the mii's, p much. Actually I kind of hope that if we can wear makeup that we get a good control over how we look and the design we can wear each day :3 BUT still I hope we don't get to alter too much, I'd like to keep the protagonists the same overall, but still, minor changes I'd embrace.
I really hope we do because the character in the trailer looks god awful. >< I doubt we will though knowing nintendo -.- such trolls they are....Did anyone else notice the first clip in the trailer where the player is standing in front of a mirror? Maybe this means we might finally get customization.. Hmmm
I would say having shops, but also it would be cool if there were like unlockable items kinda like now B/W2 had the medals.
ps unlocking a Chespin hat is mandatory :)