In addition, Alolan Form Raichu gains a new ability called Surge Surfer. This ability doubles Raichu's speed when the move Electric Terrain is active. This can make an already fast Pokemon even faster. And now having Psychic-type attacks in addition to powerful Electric attacks is going to greatly broaden the builds available to create when training your Raichu in the Alola region.
I'm not sure how I feel about the new ears, but the design overall is cool. I really like having a Psychic-type Raichu. This has always been one of my favorite Pokemon, and one of the ones I'm most looking forward to training in Pokemon Sun and Moon. I have a feeling that this could be a very competitive Pokemon.
Spoiler: He would be!