Have to agree, SM was awesome and it holds some of my precious memories from my time playing WoW.
/equip rose-tinted glasses
But all the new spells and buffs, plus the heirlooms and everything has made everything so easy :c I want more challenge while leveling! Stupid blizz removed most of the elite mobs from azeroth, and no, I'm not using heirlooms while leveling but it still manages to ruin my experience since everyone in LFD is wearing it. And no one wants to level slowly and without heirlooms with me /sadface
/unequip rose-tinted glasses
So, yeah.. SM is awesome, all parts.. Maybe not GY so much though! ^.^
Edit: SL and MgT is tied for second place, MgT might have been more fun since I used to play fury warrior in TBC. And doing MgT with less CC than you could have was awesome/challenging o: