As announced in some other thread I planned to check out the DKs and so I am.
At the moment my Troll DK is lvl 62 and questing in Zang. On the whole I think Blizz made a very nice class. It is quite overpowered if you ask me, so I wouldn't be surprised if they nerf it at some time in the future. Nevertheless it makes leveling easier which may have been intended. Yes, some quest areas can be annoyingly crowded at peak hours.
Still since many race level their mains to 80 it isn't too bad. What I don't like playing WoW again is all the annoying kids with their /spit /laugh, lol noob behaviour. I haven't had anything like this in WAR. I haven't been in Northrend much, the new continent, but it looked pretty nice the few hours I spent there.
In conclusion, I will spend less time playing WAR but have no intentions of ending my subscription.