So as everyone knows Frost Death Knights have a lot of bugs, and I'm making this topic so staff members can fix them because lot of people want to play them.
Howling Blast scales badly with attack power, thus making it hit 30% less than it should. Example: With mastery build with almost bis gear HB hits average for 18 k and crit for average for 45k while if you check World of Logs average HB hit of masterfrost death knight is about 30k and crit for about 65k.
I'm not pretty sure how haste % calculation should work for Frost Death Knights but if you compare haste % of DKs here and some other from retail guide on YouTube, you can pretty much see that they have about 60-68% haste even with some low level gear (about 380-382ilvl).
Raise Dead and Army of the Dead:
Ghouls summoned by those two abilities should besides melee attack also use attack called claw. Also Raise Dead ghoul sometimes bugs and just stands in one place.
I'm not sure if many people know this but you should be able to copy very few of boss abilities such as Shattered Ice from Hagara.
Blood Tap should instantly refresh 1 Blood rune that is recharging and convert it to death rune for 20 sec or until it's consumed. Since Frost DKs have death runes instead of blood, Blood Tap should refresh 1 Death rune that replaced blood rune which is recharging.
There are a lot more of bugs on Frost Death Knights and I will update this bug list from time to time. Feel free to add some more bugs that I have missed.