I like the idea of the original, raw and angry sound, and it fits the songs and the mood well. My main gripe is that the songs really should have been edited down, a LOT. James has even said that upon reflection he wished they had made it shorter. If it was more punchy and to the point, it would deliver it's message much more effectively, but some songs are just so dragged out that it makes you resent the production so much, especially without solos and leads to make interludes and bridges interesting. It should be a 40 to 50 minute album, not a 70 to 80 minute album.
Also, I have heard live versions of some songs like Frantic and Dirty Window that sounded much tighter than they do on the album, and Kirk throws in some leads and solos, and it made the songs sound to much more dynamic.
St Anger is a very flawed attempt at what could have been an absolute classic. That said, there is still some great stuff in there if you can be bothered finding it.