-- The film gives most characters-- except Wolverine-- very little to do. Cyclops in particular is left without a single real bit of heroism to perform. However, Hugh Jackman is a very worthy Wolverine. A great Wolverine, really. If one character is going to shine at the expense of the others, I'd pick Wolverine. I just wish they'd added ten more minutes to give a little more time to Jean Grey and Cyclops.
-- The plotting is very sloppy and slapdash. The main plot-- involving the "Mutant Registration Act," presumably right-wing anti-mutant Senators, etc. -- is laughable. Sure, it's from the comic books. But not every dopey plot from the Comics is fit for mass consumption.
-- However, the film ultimately works. The characters, god bless 'em, are fun to be with and interesting. While Singer doesn't really deliver much on action, or plot, he definitely gets the soap-opera Mutant-Melrose-Place aspect of the comic. It's sort of fun, in a guilty way, to be drawn in to a who-likes-who-and-who-might-cheat-on-who story with mutants.
