TuanHA,
I talked to a Rank 1 x6 Frost DK and I asked what his rotation is, this is what he said
Casterserennia:but usually
Casterserennia:its necrotic unless you have killing machine proc
Casterserennia:if no death runes and no proc, frost strike
Casterserennia:if no runic power after all that, then oblit last
Casterserennia:and prioritize km procs for oblit
(I don't know if this is how the frost rotation currently works but better safe than sorry

)
Why he uses Glyph of Outbreak:
Casterserennia:i use glyph of outbreak because it lets me skip the buildup diseases almost always
Casterserennia:since runic power is so abundant in arena
Casterserennia:due to 2pc arena bonus
(idk if your CC supports it)
Necrotic Strike Usage:
Casterserennia:if youre against a team without a healer or hybrid healer
Casterserennia:just do 1 necro debuff
Casterserennia:and keep it on to slow cast speed
Casterserennia:and prevent minor healing
Casterserennia:like from recuperate for rogues, etc
Faargo:yeah that makes sence
Casterserennia:if youre against a hybrid healing team, just treat them like a healer and stack necros
Casterserennia:if you stack necros vs rets, its much easier
(maybe a hotkey to switch rotation for this? As you can't tell what we are facing in Arena... idk its a suggestion!)
He is live now and you can ask him questions, he will always answer usually (remember hes a frost DK not unholy)
serennia on iNSTAGIB [ [url]http://instagib.tv/serennia ][/url]
Here is his armory:
Serennia @ Tichondrius - Community - World of Warcraft