It's quite an old movie to be honest. I think that for what they had available at the time, it's reasonably well done.
It's interesting to note that while today we have computer graphics and it would be possible to make better movies, most of the times what happens is that the CGI is used to create unrealistic sequences.
The Pearl Harbor movie for example. On one hand you marvel at how nice the planes look, on the other hand you can't help but notice that the protagonist's squad are flying Spit Mk.Vs in Battle of Britain as he takes on the entire luftwaffe on his own, while his squadmates crash all around him
It's not that we don't have the means, it's the fact that they're taking shortcuts with their research resulting in inaccuracies and altering things to make it more of a "show".
However, i think the remake of the Dambusters movie will be good as it's being developed by Peter Jackson (the guy who directed the lord of the rings). In the final LOTR movie they decided to make a 1/72 scale of Minas Tirith (the white city shaped like a tower) instead of making it all in computer graphics. According to Jackson with computers you must place everything by hand. Miniatures are extra work initially, but you have the chance of getting some really good shots when rotating the light sources around it and playing with ambient lighting and backdrops. In a computer generated scene, you'd have to specify it all manually in the rendering software.
Furthermore, apart from being a director who knows how to optimally blend CGI and scale models for his special effects, Jackson is well known for his interest in history and aviation. He also made a small film for the WWI Anzac museum, using special cameras. Visitors of the museum sit in a recreation of a WWI trench and the film is projected on the wall, giving the impression that they are on an actual battlefield as the troops go over the top to assault enemy trenches. I think he was also involved in a project to build a replica of a WWI FE2b reconnaisance two-seater biplane, built 100% according to the original and actually powered by a restored, original WWI engine. You can see it flying, as well as the build process, on the vintage aviator website, along with other WWI planes like an Albatross and an Se5a:
http://thevintageaviator.co.nz/
Sorry if i'm going off topic, but i got a sudden memory flashback and i thought people who don't know about the dambusters remake might be interested. I think it's encouraging that a person with such a background is doing it.