sure, at low mmr which you probably play. Just like warlock is immolate chaosbolt conflag win. DK are strong atm, but probably not as strong as warlocks overall.
Whats your definition of low MMR? Curretly I am yes quite low as I havnt played pvp on my DK in ages. But im aiming to hover around 2k ish. So do you think frost or unholy would be most suited for 2k+ ?