If nothing else,
X-Men: The Last Stand provides an important message for the throngs of teens and pre-teens who comprise the majority of its ticket sales. When Iceman and Pyro have their face-off, Pyro tells his rival, "You should have stayed at the academy." His comment provides the needed catalyst to turn Iceman into a giant popsicle and head-butt the flamethrower. "You never should have left," Iceman retorts. "Stay In School" is all over this movie and should convince any on-the-fence grade schoolers to continue their education.
The relationship complications between Rogue and Iceman could have been avoided without Rogue being cured of her mutant "disease." In the presence of the mutant cure child, other mutants' powers are temporarily deactivated. Iceman should have befriended the cure child. If he was in a room with Rogue and Iceman, Rogue would lose her ability to steal mutants' powers and she could touch Iceman without fear of her boyfriend's death. If the couple wanted to get risky, the cure child could go hide in a nearby closet. Love crisis averted and they could go back to being mutants outside of the cure child's presence! Instead, Rogue turns herself into a useless human while Iceman can still chill.
Also, like any good homosexual, Ian McKellan ended up in San Francisco.