Riiight, that's why people have to abuse systems like permanent world buffs to beat content?
That and up until Naxx people were playing pre-Naxx content with post-Naxx talent and class updates/buffs due to the 1.12 client. It's not the same as vanilla, where for example some specs and talents were horrible early on.
And let's not forget to factor in horrible latency back in the days. For a big part of the game even managing 40 people and having good internet speed was about as difficult as playing the actual game and defeating a boss.