Hmmm some wow youtube content creators, let's see...
Asmongold - makes really good guide videos.
PreachGaming - provides a lot of beta content as well as dramatic wow storytellings and contests like transmog.
ZAMofficial - makes some wow stuff, but pretty general gaming content.
Qelric - produces a lot of wow content (focusing on DeathKnight)
FatbossTV - takes a look at many beta facets.
HeelsvsBabyface - is really entertaining comparison videos etc.
Hotted89 - does pvp.
ibeckman671 - makes wow machinima.
Ikkiau - does pvp.
necroxisz - uploads more beta content.
Nobbel87 - does lore vids.
SlightlyImpressive - makes wowmachinima and let's plays.
Tales of Lumin - does wow vods and let's plays.
TheDDGuides - makes lore vids.
TradeChat - does some wow news stuff but mostly general gaming content.
wowcrendor - makes wow machinima.
wowhobbs - makes cool wow content that ranges.
Those are the ones I can list on the top of my head. Enjoy