I can agree on a few things in this video, especially the part about the removal of you class identity. Back then you
needed warlocks to kill Garr, for example.
But what he forgets, and many tend to do the same, is that the community has changed. To be honest not many knew what the heck they were doing back then. Addons like recount (back then SWS_stats) were rarely used. Consumables were something expensive and only in the high end raids you could afford them, and alot of players in your 40 man raids were too poor or lazy to get any consumables at all.
The source of information has also changed alot. How many knew of BiS lists back then, or any class guides at all? You visited thottbot in hope someone before you did find the quest item and put it on the map where it was located, otherwise you had to rely on asking other players. Now we have wowhead.
Today recount is very important and a source to see who is underperforming, in vanilla, probably 80% of the people were underperforming.
Many of us want to play on vanilla servers cause of that nostalgic feel. You will never get that true vanilla feel though, since the players around you have changed. Its down to this, you will see DamageMeters everywhere and people craving to top them, improving their characters to the max, looking for BiS lists and the perfect rotation. Now, with this kind of new community, if we have blizzlike hp and damage output from raid bosses, it will be nowhere as hard as it was back then. Since we know this game so much better now. The community is what has changed the game the most.