Frustrated looking for a new start

[Aradar]

Qustion, is there any good reason I need the Lich King expansion right away?

Not that I can think of.

I see people with DKs as tanks now and it has its benefits ( ebon plague/magic resist dome..ect )

I'm not refuting what he says but since you are new to the game, Ebon Plaguebringer can be handled as well by the balance druid talent Earth and Moon. Both of these provide a 12% increase in spell damage to the group which is why they have become so attractive. Warlocks can also provide this up to 10% with Curse of the Elements (maybe more from talents, I don't know) but I guess because they are more squishy (wear cloth) they aren't as popular.