I admit as I look through some of the arguments on editions, I'm a bit mystified, as I've almost always played house rules as much as anything else.
I prefer the second edition of the advanced rules. After fighting it for years. I caved and had to admit I liked the books. I liked the fact that they cleared up some of the worst language of the old spells. I liked having the tables easily accessible. I liked the expansions I liked having the tech tables organized by era (despite the fact that I had a number of arguments with their pricing.) I liked that they had a variety of magic systems to choose from. I especially liked the character generation, because it made your character unique, without having to resort to the ever annoying multi-class. Clerics who were actually different for different Gods. Mages who had armor. All without that awkwardness of the Unearthed Arcana. Basically they gave you rules to make character classes of your own . Yes I know you made them before, but let's be honest, they were rarely balanced. They were mostly just a bunch of cool powers you'd get and no real flaws. I think these editions really made it easier for players to visualize their new character.
Now I admit the multitude was confusing at first. Then I realized you didn't use it all at once. You, as the DM, picked what would be in the world. It really breathed some air into the game. It made magic unique again.
OK, I still didn't really change from simple combat.