Beyond that, it's problems were mostly due to lacking rules for stuff:
-No rules for tripping, pushing, grappling
-No rules on how much magic items to give out at what level or what items are too powerful
-No way except through experience and guessing to know exactly how powerful a particular monster was
-No rules on what constitutes a fun encounter, how many if each creature would be good before they'll be overwhelming, and so on
-No rules on creating, buying or selling magic items. The game says that magic items aren't bought and sold, but adventures hand out so many of them that the PCs will have hundreds of them with no way to get rid of them.
Oh, man.
You just hit on all the reasons I LIKE 2nd Edition! Let's break this down:
1 - "No rules for tripping, pushing, grappling"
1st and 2nd Edition both based their combat system on Douglas Fairbanks style swashbuckling. The rules presume there was much back and forth within each round (hence the reason one round = 1 minute). Jumping, flipping, somersaults, trips, pushing, scrapes and cuts where all left to the mind's eye.
2 - "No rules on how much magic items to give out at what level or what items are too powerful"
Why would any self-respecting DM want that? Magic items should be rare and mysterious.
3 - "No way except through experience and guessing to know exactly how powerful a particular monster was"
Huh? Are you talking about players or DMs? A DM can assess a monster in seconds by considering it's Hit Dice, which translate to experience level, and then consider any special attacks and defenses that might cripple their PCs.
4 - "No rules on what constitutes a fun encounter, how many if each creature would be good before they'll be overwhelming, and so on"
Oh? So... which edition finally unravelled the "secret formula for a fun encounter"?
An encounter is just an encounter. The way the players deal with the encounter determines whether the encounter is any fun. 3 1st level Wizards encountering a party of 200 Orcs can be a fun encounter, provided the players aren't stupid.
5 - "No rules on creating, buying or selling magic items. The game says that magic items aren't bought and sold, but adventures hand out so many of them that the PCs will have hundreds of them with no way to get rid of them."
See #2. In this case, it sounds like the problem is the DM, not the system. Stop giving out so many magic items if it's become such a problem.
If magic is so common in your world, magic items would be cheap. Maybe you shouldn't even call it magic!
Personally, I imagine my worlds as not only low on magic, but also low on equipment. It's not often you'll see someone in my games carrying a sword. Swords are for the wealthy. Even less common is metal armour. Nobody wears metal armour unless you're in the army, or a knight. The average blacksmith can't even make armour. You'd probably have to go to a castle. And it will cost a fortune.
Seriously, why do some people insist that everything be regulated? Why do players have to have special abilities to have fun? Why is it that combat is increasing becoming the central focus of the game?