When Ash meets Pikachu in the original anime, Professor Oak has a neutral and stern expression as the 10 year old was gushing over his first Pokemon. When we see things from Pikachu's point of view in the trailer, Oak has a more defined frown and is looking off to the side, as if he thinking, "Boy, you have no idea how much trouble this one gave me." Which means he will still be kind of a dick for not warning Ash about Pikachu's electrical powers until he is in the process of being shocked.