This discussion stemmed from the minecraft-feed-the-beast tag. I'm subscribed to minecraft and like answering questions on the tag; however the "Feed the Beast" mod changes the game to such an extent that no matter how much I know about Minecraft, I can't answer any questions regarding "Feed the Beast".
So this discussion can be generalized. If a mod, expansion (or DLC for that matter) changes a game to such an extent where if questions are tagged with the mod/expansion/DLC name, that the question will have nothing to do with the base game; then the base tag of the game should be removed from the question.
We have already done this in the past, consider the Warcraft 3 map dota no longer carries the warcraft-3 tag, since knowing Warcraft 3 strategies does nothing to help you in DotA.
Unfortunately I don't have any more examples right now, however I still think it would be good to generalize this rule.