See, for me the film works. I liked what they did with the story and I didn't mind the lack of character development for the supporting cast because I didn't care about the supporting cast. My only real problem with the film was the pace/running time. It moved too quickly but still [surprisingly] managed to deliver some pretty intense/emotional moments - and I credit that to the fact that we already had an existing relationship with these characters.
I think people seem to think Ratner set out to change everything Singer established but I see it the other way around. I think he basically tried his best to do "a Bryan Singer film" with less time, more characters and very high expectations from an already displeased fanbase (since Singer left).
Personally, I think alot of the fans went in to X3 ready to bash it. I say that because the second time I saw it I went with some friends that avidly read comics and they were badmouthing it on the way to the theatre.
For me the emotional intensity made the film work. And John Powell's score