5s cd on howling blast is a step back indeed, but most dk abilities are restricted to be used 2 times each 10 seconds so its not that far fetched. Lately i had a look on what build etc the top dk dps was using and alot of them seem to use a dw frost/unholy hybrid build where howling blast was about 40% of their damage. Dont take this statement to serious though since i was just looking at some wws charts so there could be that it was just the players who where good and not the spec etc...