Even Disney magic isn't forever and pixie dust doesn't perennially bubble out of the ground like water from a spring. And with the 1995 "Pocahontas," Disney's 33rd animated feature and the latest in the increasingly popular modern series that has gone from 'The Little Mermaid' to "The Lion King," the spell, though hardly broken, is showing increasing signs of wear. Not that "Pocahontas" won't justifiably delight children or is lacking in its share of animation's good things. Among its strengths is a gorgeous look, replete with sweeping vistas and colorful panoramas, and a fearless, strong-minded and athletic heroine (albeit one whose form-fitting buckskins make her resemble a close personal friend of Fabio's). But adult viewers, spoiled by what has come before, may feel that this film, which relates the legendary romance between a chief's daughter and English adventurer John Smith in the New World, is more by-the-numbers than inspired (ABC Sunday at 7 p.m.).