I always considered 2.0.1 and 2.0.3 to be part of classic because the gate to Outland was not open. Could Druid bears or Prot Pallies tank at that point? I know there was lots of QoL improvements added that didn't ruin the social structure, exploration, and game play. and classes were more balanced out. Technically since the gates were not open it was part of Vanilla for a little while so all of this should be completely acceptable by you "purists". Most of the things were addressed QoL wise by that point except set drops for different specs in old raids.
Get your torches out "purists" because I just committed heresy.