While there's the least obvious that Aladdin here has changed from Chinese to Arabic (as most adaptations did) but now let's see the differences... aside from Abu and Rajah. In the original, Aladdin's father had died and his mother was shown in the fic. In the movie, Aladdin was thought to be an orphan at the streets (homeless urchin) until the Aladdin and the King of Thieves movie. So pretty much, much a difference. Also Aladdin doesn't meet Jasmine earlier, he was a child at the beginning of the novel. Jasmine was also shown to have been paraded when Aladdin first saw her.
The first is the Genie. In the original story, there is the Genie of the Lamp and the Genie of the Ring, two genies. The Genie of the Lamp in the original story grants unlimited wishes, the Disney's Genie only granted three wishes. Also, Disney completely removed the genie of the ring and created a sentient magic carpet in its place.
Another great difference is Jafar against the unnamed sorcerer. While Disney usually waters things down like the Hunchback of Notre Dame, however I'd admit the whole story of Jafar is something. Jafar is the royal vizier and the magician combined. In the original story, the royal vizier's son was arranged to marry the princess but it was foiled by Aladdin. In Disney, Jafar is a pedophile pervert who is in love with the 16 year old princess not only for the throne but also because he's a perverted pedophile. Also one untold ending was that the sorcerer had a brother, Jafar had a sister named Nasira instead who only appeared in a PS1 game, not any of the official series.