Well it's not that easy anymore. The other side is gone and we have never seen anybody come back from being all the way dead. I guess we'll see, but I really hope whoever dies from now on will actually stay dead.
Technically it shouldn't even be possible to add more witches to the ancestors anymore. Without the other side the spirits should be long gone before you can consecrate the bodies. Unless there is some magical waiting room for New Orleans witches or something.
Once an episode I think that Vampires should just drop dead in that bar. Guess the anti-magic thing is very selective.
Those are pretty bad examples. The writers didn't ust forget those things they wrote around them and not even that badly.
That Klaus got somebody pregnant was treated as a minor miracle and the theory is that it's because he is half werewolf, so still kinda alive, a little.
Witches usually can't be vampires at the same time, since they draw their power from nature and Vampires are an abomination against nature. But the heritics don't draw their power from nature, they siphon other magic.
