Huh, this sounds very similar to Axe of the Dwarvish Lords, published (I think) 6 years later. Axe of the Dwarvish Lords was an adventure for levels 13-15 that took place in a huge mountain complex mostly populated by goblins. Ordinary goblins.. with attitude.
From the sound of it, Axe of the Dwarvish Lords was more sophisticated, in terms of meeting the reputation of Tucker's kobolds. But it did "cheat" as well, in the form of additional rules for the goblins. The new rules were interesting though, and I remember noticing several years ago how they were pretty much precursors to 3E combat options. Examples escape me at the moment, sorry.
It's funny that they would make basically the same adventure again if the first one was so unpopular.