I've just finished listening to the most recent Bad Dice podcast in which they have a long interview with Gav Thorpe of GW and Mechanical Hamster fame discussing games development and the general workings of Games Workshop.
The interview is extremely interesting to listen to and includes a lot of insight into the structure of GW (at least up to the point at which Gav Thorpe left), their methods and practices as well as going into a lot of detail as to some of the reason as to why GW has not/does not publish large scale online/print changes to Codices/Army Books with the introduction of a new rules system. I found this part of the interview quite enlightening and can see the points that they are trying to make.
I also agree with the thoughts of the hosts towards the end suggesting that GW could do worse than considering publishing/allowing more similar interviews to this to give people an insight into their workings and reasoning, something that would very likely reduce the amount of hate and vitriol that seems to be aimed at GW from many corners of the internet.
I'm very much aware that some of you may not be the biggest fan of Gav Thorpe after the Chaos Codex posts (1 and 2) he put up on his blog and his handling of that, but I would still strongly encourage you to give this interview a go and listen to what he says.