Blood Plague

Is it necessary to keep it up outside of Outbreak as Frost? or should Death/Unholy be used for Obliterates and Necrotics?
Deleted by Derpenstein
if you're going to use obliterate at all, the modifier on having both diseases up is significant.

Since you mention necrotic strike, I assume you're talking about pvp. Read the other recent thread about no longer using obliterate. I think it is possible to rely on howling blast, necrotic strike, and frost strike and be successful in pvp.

In PvE however, not at all. And again, if you're going to use obliterate at all, pvp or pve, you really need to have both diseases up.
It is just 1 UH rune every 30 seconds. For 12.5% stronger obliterates for that whole time (which is quite a few obliterates in 30 seconds) It's too much of a DPS loss to not use it. You are going to have to face the fact that you are going to be using runes on things other than obliterate. Always keep diseases up and use pillar of frost every time it's off CD.