U r speaking about unholy or frost? Becaust (in my opinion) frost it's like that.
Depends on what you want to be, i mean if you like a mele class i think warrior could be a really good option, but if you like range maybe hunter or warlock, hunt is very easy to play but it does'nt have much supervivence like the warlock or even a shaman, Becaust? Hunter can't heal it so much, just run
If you want pve with range class i recommended a hunter or warlock, are very funny to play, i start with a hunter and i still loving it.
If you want pvp its better a hunter or mage (have more difficult but still you can try with this).
From a mele class i think warrior (for dps) can be the best option, they have a loot of damage and supervivence, defensives, cc, etc... (PvE and PvP).
Tank your better option it's a blood dk, they are very easy to play..
A healing class could be the monk, it's very easy to heal with it, and the mana it's not a problem