Simple Q&A Q605 continuation (PrCs and lost entry requirements)

[Random832]

You're right, this is going past the scope of Simple Q&A.

Prior discussion

Well, if I'd actually gone to look at Dragon Disciple, I'd have noticed the usage of the word "already", which changes the meaning of the prerequisite significantly - it therefore explicitly refers only to the situation as it was at the time the class was entered. You do not, by becoming a half dragon either by attaining the tenth level of Dragon Disciple or by any other means, cease to meet the requirement of not already being a half dragon.

This doesn't resolve the issue with Ur-Priest, since you clearly do gain the ability to cast divine spells (I would argue that it's certainly not intended to allow you to subsequently gain such an ability through fresh multiclassing into Paladin (well, Tyranny/Slaughter anyway)/Ranger/etc, either, though as a matter of fluff I'd say that Archivist is an open question). But I still think that the usage of the term "or the like" does allow an interpretation that there are some prerequisites - such as negative ones like this - that this does not apply to because they are not "like" those listed.