Just to get my two cents worth:
2nd Edition = more bulky than 3rd Edition.
I've had an infinitely easier time getting people to understand the rules of a CRPG based on 3rd Edition rather than AD&D.
I mean, that +1 bonus with your sword lowers your THAC0 by one. Talk about intuitive. And the bizarre saving throws, which despite my many times of playing BG and BG2 I never really fully understood, was crystal clear.
If you get an item that provides a -1 to THAC0, among other goodies, is it a compromise to the other nice abilities making you think about using it, since you'll hit less often? Or is it just another buff? -1 to THAC0 is nice, but often when stated like that it means a penalty.
Not to mention that better armor provides you with less Armor Class?? I guess less is more!
Sure, after you get used to all these rules it's no problem. But if anyone claims that they made perfect sense out of all this their first time looking at AD&D rules, I say they are lying. There is nothing intuitive about an INCREASE in Armor providing a LOWER number. It might seem that way to us now...but that's only because we're used to it. Show two people that have zero familiarity with D&D, and all other things being equal, I guarantee the 3rd edition player will grasp things quickly...especially if not being coached by someone.