I thought the same thing. Then I realized that the instance itself won't be anywhere close to as cool as the video either, so I figure I won't miss much.
I probably had a better experience of that instance than anyone that actually goes there. It's all good.
Actually, I wish they would put out videos like that for all the instances, even the old world ones.
The style and feeling match the Rufus Cubed gang that Blizzard hired to do gameplay reels after they won the video contest with The Return. I imagine this is proof of concept for further story-based content introductions... much better than the strictly play-based stuff they did for the Eastern Plagueland "World PvP" addition.
I've thought for a while that MMORPGs would be well served to hire a few machinema whizzes to do promotions like this on a monthly or even fortnightly basis. Offer player cameos to folks who win contests or complete certain in-game events... promote seasonal changes, patch additions, and history injections via visual storytelling. Let's hope that Blizzard not only continues this trend, but inspires other games to copy them.