Though I hope a lot of this is true I have some doubts, complaint, and hopes. All of which will probably be shot down in a few days time.
The hero classes do sounds very interesting but I hope a death knight cant be selectable by all classes. (Odd for a druid to suddenly be a death knight as someone said before)
Rather I think it would be a better fit for say a shaman to at 80 to become a far seer, a rouge a blademaster, or a lock a necromancer or lich or maybe even the deathknight. I think the old Secret of mana game did that and though you picked your class you went into it was a cool system.
However if a deathknight class specifically were to be universally pickable by even only the high levels with content unlocked... How would the alliance use them? Warlocks are one thing but think WarII. Palis were the opposites of DKs. (Which raises the question why were shamans put their and not DKs at first... Oh well different topic and obviously not my best argument now that I look at it.)
But for people who would be skipping the 70 stuff I hope the green items you get from quests wouldnt be as uber as the epics you would be getting from BT. I understand the reasoning for it but I would rather have early 71 on be super easy for Black temple runners and medium for skippers than equal. (Skill aside just something that bothered me nothing big)
As for the new profession I doubt the buffs would be huge more like enchanters enchanting their own rings.
Next up... I personally I would much prefer a WarIV hero taking down arthas or no one at all. Archimonde annoyed me a lot (not to say I have beaten him or even attempted) in the sense that even with help he is even phased. I am remembering the last level of WarIII RoC that when archimonde came in your base with divine armor you went to your next place to defend because that first human base and second orc base got fucked over quickly. My point being 25 footmen / mages / tauren etc etc beating (killing or not) a badass from the lore isn't as pleasing as an epic cutscene of sorts. ( Oh and I realize the players dont really kill archimonde but... Think about a lowly non hero taking a smack from one of the most powerful being in existance and 'tanking' him.) Oh well another personal annoyance.
Lastly (finally I know) I would hope before northrend is overrun with raids that the naga / ashzara / old god water elemental version of ragnaros (I think that has pretty much been said by now with the 1000 hints) aren't forgotten. I hope all understand that lady Vashj was not the leader of all the naga and that very cool (maybe underwater ) fights may remain.