Xath said:
What would you do in this situation, then?
...
Every WotC published book is fair game in this campaign, with 3rd party stuff being allowed on a case by case basis.
From this statement, I would assume that the CW rule applies, but I would definetally check with the DM to be sure. In games I've played in, this has actually never come up. If it did, I assume we would do as Kahuna Burger describes and decide on a case-by-case basis. The rule does make a certain amount of sense, it's just dangerous as a blanket statement.
Goobermunch said:
That's the problem with any transformative prestige class. But that's also an edge case. Aside from the Dragon Disciple (which, as noted above is a transformative class), are there any other prestige classes that would violate the Complete Warrior's rule?
The Dragon Disciple is the only case that I know of that causes complete rules meltdown. However, there are a number of other ways you can create cognitive dissonance if you try. Any PrC with a racial requirement can cause problems if you change species somehow. For example, this means that any (epic) monk that reaches level 20 and becomes an outsider loses any PrCs that had a racial requirement, which is just silly since they still have the same body and training.
There have been other PrCs that appear in later splatbooks, like Races of Stone, with effects similar to the DD (i.e. racial requirement, but race is then changed). However, in all of the cases that I have found, they added in a note specifically stating that the racial change does not count towards meeting the prereqs of the PrC.
WotC could certainly add a lot of credibility to the CW rule by errataing the DD to add a similar phrase. Just as easily, they could also add the CW rule to the errata to the PHB or DMG to remove all doubt. For whatever reason, they have chosen not to do this. The fact that they have added errata to the PHB since CW was released is proof to me that CW rule is a variant, and is not included in the core books on purpose.