What’s Changed for Frost in 4.0.1

As I continue to hit stuff in Frost spec, and read more EJ things, I keep noticing things that changed from pre-4.0.1 that might not be so obvious. So here’s a list of the changes and a brief explanation for each one. I’ll update for any changes I notice in future/commenters make me aware of.

Big changes to Death and Decay

The List:

• Use KM procs on Obliterate rather than Frost Strike. With the new patch and talents, OB hits harder than FS, so all Killing Machine procs should be used for OB. Do not, however, wait for OB runes to come back up if you can FS. Delaying attacks is almost never a good idea given how close to GCD-capped the rotation is.
• Frost Fever no longer HAS to be up for us to do any semblance of damage. Yes, diseases are still great, but the talents that buffed our damage by a lot when FF was up are no longer, so it’s safe to DPS down low-health adds without applying diseases. If you’re using Glyph of HB, however, you’re still going to be applying FF as you run towards the adds anyways.
• Don’t pestilence for low numbers of adds, just HB+tab cast Plague Strike. Pestilence lowers disease damage by 50%, and so now it actually is more profitable to cast PS, tab, and cast again. HB glyph takes care of FF, and when casting lots of HB vs. OB you get excess unholy runes, so use them on PS.
• Howling Blast is no longer affected by Killing Machine. This is a bonus for single target damage but a big loss for AoE damage; no longer can you crit on 10 targets at once with one HB. Frown.
• Death and Decay costs one Unholy Rune! Holy crap. This is what happens when you don’t pay attention to changes for a while, then log in and have a number of WTF moments at the things that changed. Obviously, this makes it a lot easier to fit into AoE rotations, and so should almost always be used. Especially true because HB-AoE rotations leave excess Unholy Runes, as mentioned earlier.
• AMS no longer energizes us with RP when absorbing damage. It only does so if you have the talent in deep Unholy. This sucks, but really, we have few excess GCDs so it’s not a big thing.
• Runic Empowerment means you have to stay on your toes. This is a change for all specs, but it means that your rotation is even more priority-based than it was in previous patches. Having random runes popping up unexpectedly (and with no internal cooldown) is both a frustrating and incredibly rewarding experience. It really makes DPSing more interesting than it was previously, and also makes the ability to see runes clearly (requiring a good addon, Magic Runes being my favourite) and react quickly a lot more important than pre-4.0.1.

What else have you noticed that’s changed for Frost, or DKs in general?