I have to admit I had a *lot* of fun with both 1e and 2e. I don't know if it's just the nostalgia of being able to game more than once ever 5 months or so, or just that I and my players really didn't care much about real world balance being in games.
But now that 3e is out, I have a comparison to match 2e up to, and many, many problems surfaced when I saw how much easier, and more detailed the new edition had become.
So, a list of what I didn't like in 2e:
1) THACO - Mentioned before, same deal. I had to explain (and have it explained) to many players over and over just how to break the convuluted system down to hit something.
2) Minute Rounds - I never liked the 1 minute round, mostly because nobody in their right mind would move that slow in a battle. Peg-Pelvis Pete could hop up an downward escellator in less time than it took you to slowly walk up to something and take a solitary swing. Even worse were Turns.. Great-yapping-kobold-GOD! Anything that took a turn to either take effect, or for the effect to wear off would grind the game to a halt.. If you had a character under a spell that would last a turn, you might as well break out the camping gear after the battle, because you'll be there for a freakishly long time. If I remember correctly, a Ghoul smacking you around would cause you to be prone for damn near half an hour if he got in a couple of good whacks on you.
3) Weapon Proficiencies - As was stated before, I didn't much care for the 'specific weapon' proficiency that even fighters (oh.. Sorry, Warriors) were restricted to. While I believe it takes different styles to *skillfully* wield different weapons, like being a master swordsman, or super deadly with an axe, that should have been left to a specialization. It was silly that a big brute could pick up a sword and skewer anything if he was proficient, but would get slapped around by an anorexic wizard if he picked up an axe that he wasn't proficient in.
I partly love 3e because you even have sub-rules for using chairs and tables to smack things around with! Fight dirty!
4) Wizards - They were utterly pathetic in 1e and 2e. I only used the splat books later on in 2e, so for the most part, wizards would have 1 spell at first level, and that's it.. The best HP you could hope for? 6, and that's with an 18 con even due to the stat limitations for classes (more on that later). I've had swarms of bugs kill wizards in the old version, and I believe even a housecat took one out at one time.
5) Limited stat block - By that I mean that you didn't know, or have a general idea as to what the creatures attributes were. While 3e can get a little chunky for the big critters, 2e provided very little on stats other than HP, AC, Thaco, and any spells/special abilities the creature had, and perhaps what it was carrying in weapons and armor.. Cast a ray of enfeeblement? You have to guess just how much less damage the creature does, cast something that drains? More guesstimation.
6) Boring at higher levels - Again, stated before. After a certain level of advancement, there just was no point. For most classes once you hit 10th levelling was just a pointless excersize in garnering either spells, or getting a better thaco. HP became useless, as did good Con scores at that point, because you only recieved a fixed number of HP per level. You also didn't really get a hell of a lot in the way of abilities, or really cool new things.. You simply got slightly tougher. I don't think we ever played past 12th level in 1e or 2e.
7) The Finite Infinite - I used to think of experience in that way. It was a finite number that took an infinite time to reach depending on class. A friend and I were remeniscing about our last 2e campaign, in which it took us 6 years of playing to get to level 9.. 6 *YEARS* of real life to get to that point while playing casually 2 times a month, sometimes more. Wizards lagged behind the clerics, thieves and fighters until a certain level when they went up quicker, and fighters got bogged down, leading to badly mismatched parties for extended periods of play.
8) Racial caps - A rule we always ignored in 1 and 2e. We just couldn't justify why certain races could only get to a certain point in level progression, where humans could blow right past them all the way up to 20th level. Were elves that weak? Dwarves just too dern stupid to become high level wizards?
9) Multiclassing/Dualclassing - Nuff said about that. I've never played a multi/dual classed character in the old editions because it led to much weaker characters.
10) Druids - Pretty much useless, and overlooked in the old editions, because of their insane need to balance everything. If their alignment was taken to it's full meaning, you'd have to kill a paladin every time you killed an orc, or the world would spin off into the sun.
11) Poison - Heaven forbid something poisoned you in 2e, or you'd be toast. The insta-slay poisons tended to be AWFUL at laying waste to parties of people under 5th or 6th level, because nobody had anything to fight it with save slow poison, which in turn meant that you had to get back to town quick or die from the effects
12) Clerical medkits - Clerics were simply medical kits. They served very little purpose outside of that in 2e I found. Yes, they turned undead as well, but they had to chew up terrible amounts of space with weak healing spells to make sure the rest of the party didn't die. Add to that a Thaco that wasn't really all that hot to begin with, and they turn into well armored pharmacies.
13) Orc and Pie - The orc and Pie module in 2e was HORRIBLY broken. The orc always blinded the party with the pie, which had poison in it, killing the lead fighter, then took an hour to run across the room, open the door, and escape with the party in persuit.. Worst $35 I have ever spent!
