Ending seemed very rushed
Compared to other Disney movies, it seemed that the film very quickly wrapped up its story nearly as if someone pressed a button marked "finale" all of a sudden. Stitch did a complete 180 between the monster trying to pretend to be a family pet and deciding he'd in fact be a family pet way too quickly. Also the social worker didn't seem to have any reason to change his mind about Lilo and Nani, alien or not (yes he used to be a CIA agent but that was his past). Nani really did seem to be a terrible carer for Lilo, but obviously because it's a kids film this couldn't be the way it ended. Some development seemed to be needed to show the social worker that Nani had any redeeming features in terms of actually taking care of Lilo though to make the ending believable.
It seemed like after having worked up such a serious plot (Lilo about to be taken away), they suddenly found they needed to stamp a happy ending on but didn't have enough screen time left to actually develop it. A bit disappointing.