The Greyhawk setting is designed to be toyed with. Jumping back before it was overly detailed the concept was to have a skeleton of a setting that the DM could flesh out and make his own.
Have to it with the Temple.
The Village of Hommlett is a favorite of mine and other than adding names and some details I haven't felt the need to change much, but I've always reworked the Temple to suit myself.
The supermodule has the temple developing rather quickly (while I much prefer having the temple as an ancient structure that even predates humanity. I also like tossing the Cthulhu mythos into my Greyhawk campaign which I've felt works like chocolate and peanut butter).
The first defeat of the Temple is loosely described and little directly about the battle of Emridy Meadows. No need to worry much about contradicting the written history (from published material) or, honestly, of worrying about being tied down what little there is of the history as written.
The Temple draws evil to it and I've always felt that regardless of how many times the evil is defeated, evil will return (which allows for an excellent source of future adventures).