Hi,
Not exactly sure what you are calling 'classical' approaches.
Von Weber did the best work I've seen on bureacracy, and humans haven't changed appreciably in the last century. He's still certainly relevant.
I guess the bottom line is, if you aren't at least aware of the 'traditional' approaches to organizational management, you are unable to examine alternatives with any real base of reference. The key factor to look at is, they are called 'traditional' because they've WORKED for long enough to become 'traditional'.
Good Luck!
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