Sure, I know differently now, but in looking back there were many things in AD&D that encouraged min-maxing. All of which made the game less about the players and the roleplay and more about the characters and the rollplay. It was like Spinal Tap and "this one goes to Eleven". And we had no idea.
Myself and most of my gaming circles at the time cut our teeth on AD&D. Basic D&D was a child's game to us (we were after all, teens, and it was important to play an "adult" version of Dungeons & Dragons.
Unearthed Arcana came along with weapon specialization and barbarians with a d12 HD and doubled bonuses for Dex and Con and we almost saw the issues. Almost. We quickly banned cavaliers and barbarians (and no one wanted to play a thief-acrobat, so it was a non-issue) but the new spells, new character generation, weapons specialization and the like? We kept it all. It fed our teen desire to be even more better. More super.
Now I look at 5e, and in many ways it makes me think of 1e. It's certainly closer than 3e or 4e are to that venerable edition to the rules. Except now, with 5e, stats matter less and all characters are damn near super.
Which is why my OSR clone of choice emulates pre-1e. I want exceptional players more than exceptional characters these days...
(not that exceptional players CAN'T have exceptional players - it is not mutually exclusive - I just want to emphasize player skill over character abilities in my old age)