Seriously? I can't think of anything I hated more about AD&D.I miss the plateau effect of negative advancement. Where you got your character's up to between 10th and 15th level and simply remained there because you were constantly loosing levels vs undead or resurrection or what have you.
I'll join the choir lamenting the lack of spare time to play several times a week. Apart from that I don't miss anything. The changes from one edition to the next so far matched my changing preferences.