Whatever pompous opinions you've read or seen from critics about the new Clone Wars movie, ignore them. If you're a Star Wars fan, you'll enjoy the movie. End of story. Besides, as a Star Wars fan, you should know the mainstream critics aren't going to get the movies anyway.
I think what the problem is, even with some fans of the franchise, is that perfection is expected and when perfection isn't received, the material is automatically deemed substandard and not worth anyone's time. The thing to remember here is that George Lucas approves every bit of Star Wars anything that is released, be it novels, comics, movies, or shows. If characters die, he knew about it and was okay with it. If certain things happen, he knew about it and was okay with it. When new stuff comes into play, he knew about it and was okay with it. Just because you don't like it, doesn't make the whole thing bad. Just because you disagree with it, doesn't mean it should never have happened. If George Lucas approves of it, we should approve of it, too. After all, it's his universe. Now, if it is the case that you don't approve, you can just choose to forget it even exists, like I have chosen to do with the events of The Crystal Star. I guess it just depends on how each fan chooses to treat Star Wars. I treat SW like a sweeping tale of fictional history. I'm always eager to learn and discover more, and I take all of it in stride. With the exception of the aforementioned novel, I have never had a strong objection to anything I've read or seen. I love all the films and I've enjoyed every book I've read. Sure, some are better than others - and that is the result of personal preference and the author(s) that wrote each book - but that is the case anywhere. Maybe these people just need to learn to lighten up a bit about the whole thing. Remember why you love Star Wars and just go with the flow.
That being said, the Clone Wars movie tells the tale of one particular crisis. I enjoyed it because like the cartoon that came before it, it opens a window into what the Clone Wars were like. Since it would be incredibly time-consuming to capture every battle and every nuance of the wars on paper or film, these little windows are perfectly acceptable. So here's my advice: If you choose to go see the movie, don't go in expecting anything. If you do, you probably will be disappointed. Just go in hoping to be entertained with some Star Wars fare. I believe then you'd come out happy.