Have you? Let me remind you the Vanilla / TBC rotation of some classes.
Vanilla Mage: Frostbolt until oom (1 button)
TBC Mage: Apply 5 stacks of Scorch, then Fireball (2 buttons)
TBC Rogue: 4 Sinister Strike, Slice and Dice, 5 Sinister Strike, Rupture (3 buttons)
TBC Warlock: Shadowbolt until oom, Life Tap occasionally (2 buttons)
TBC Shaman: IIRC 1 macro did everything (1 button)
Correct me if I'm wrong, but the only class that even used the term "rotation" those days was the hunter, as in "shot rotation", because back then their shots paused their auto attacks, so they had to weave the shots in between the auto attack timer.
Then Wotlk came, and since then we have the classes more like they are now.
It's funny, because everyone keeps praising how Vanilla and TBC were hard and now everything is so casual, and yet the mechanics back then were extremely simple. We had bosses were the strategy was "dispel this".
NOTE: I praise Vanilla myself, but for different reasons.
So yea, as someone who actually played back then, the pruning is very welcome.
Dota heroes have around 4 buttons each, yet the PvP skillcap is extreme.
Counter strike doesn't even have spells, you really just press 2 mouse buttons. Now tell me that is a casual friendly game.
I'd rather have interesting game mechanics than stare at addons to play properly.