I know there are folks out there who think that it's so "old school" and "true" to create characters with the 3d6 in order system. I'm not one of them.
Personally, I look at it this way... It's a fantasy role playing games. Where is the fun in playing a fantasy game so you can pretend to be an average Joe? Isn't that what you are doing in real life as it is? Aren't you trying to escape reality for the time being? Whatever trips your trigger I guess.
I don't want to be Joe Shmoe in a fantasy game. I want to be that one in a million person who stands out from the crowd and has got a little more going for them than most do. Now, I'm not talking about being a "super-hero" necessarily. That's not much fun being able to whoop everything all the time.
To me, that's what being a PC in AD&D is all about, roleplaying someone who is a little bit more than average. When you roll 3d6 in order you know what you get? About average, that's what you get.
In Ad&D, average people have scores around 9-ish. Super heroes would be with most scores around 16 to 18. I'm looking for a PC with scores around the 13 to 16 range. I want heroes, not "super" heroes.
To accomplish getting "heroes", I use the 4d6, remove the lowest, assign as desired. In ad&d 1e, there are ability score minimums to play certain classes. You want your best scores to be in those areas where a required minimum exists.
I don't think the score minimums are there to ensure scarcity of certain classes though. I think they are there to make sure that when you want to play a certain class, that there are "trade offs" that keep the character balanced and focused.
No, I won't knock folks that want to play low score ability characters, but I also won't be playing in those games either. I get slugged around in real life far too often enough as it is. I want to have a chance to win a few of those drag out, knock down rounds against the world once in awhile. I wanna be a hero.