Originally Posted by
Shiira
Converting unholy runes won't be any more of a damage increase than converting frost runes.
You can't howling blast with an unholy rune, but you can't howling blast with an empty frost rune either. Converting unholy runes isn't making them any more useful overall, you will still end up with a rune you can't spend on howling blast roughly every 9 seconds regardless of how many times you have blood tapped your unholy runes.
Honestly I don't know why blood tap sims better in patchwerk conditions, it just does. Apart from the fact that it gives you resources non-randomly when you want them there are a couple of real encounter advantages that I have mentioned already, but other than that I just don't know.