Death Knights need plate because unlike Warlocks they're not snivelling wimps hiding behind a Soul Link to stop them from dying, and unlike Warlocks have the physical development to actually carry a weapon larger than an apple-corer?
(and traditionally a Demonic Pact requires some manner of sacrifice on the part of the holder....Death Knights TAKE what they want without bargains...)
Nah, whatever friendly bickering there might be, I will be re-rolling. I've never really felt fully at home with my Warlock which is probably due to it still having around 50% of the /played time I have on my Rogue and I've always prefered a more visceral style of play......You know what else? I actually need a new challenge. Being able to tank effectively and dish out outstanding melee DPS are primary reasons for the change - its another aspect of the game I haven't explored fully and to keep things interesting I need to change things around slightly.
Check out this video of a level 77 Blood Spec DK:
Another Jayde Video, More Blue Posts | DeathKnight.info
And if you get chance...play the instanced starting quests in Wrath of the Lich King. Warlocks might be bad, but Death Knights are plain evil.