Is every flaw in AD&D rules then a flaw in the DM because they enforce them?
In a sense, yes. (and sorry for my longwindedness, but...)
You have to understand, I started playing this game in the mid 70's. It was called "Chainmail" then. I watched it evolve into D&D, and then AD&D, and the first edition AD&D set are the last "rulebooks" I purchased. I'm not sure if this is true in 2nd or 3rd edition DMGs, but in mine the book stresses over and over that NO rule is to be considered "carved in stone". The DM is actively encouraged to make whatever changes he or she feels adds to gameplay. The rules (ALL of them) are put down in their simplest and most basic form so the time it takes to learn how to play is short. As the campaign progresses rules are expanded, altered or dropped entirely as the DM sees fit.
My current PnP campaign just recently turned 20. (20 years of REAL time playing at least twice a month.) Two of my eight players are originals. On an interesting side note, my newest player is the actual son of one of my original player's girlfriend! At this point, some parts of my game bear little resemblance to the game described in the DMG. Other parts haven't changed at all. Each change was made, by me, to add to the realism and character development of the game. In my world, experience, gold and levels aren't as important as real, believable character development and interaction. Thus in my world, creating a character is a long and involved process. But I have to say, as much as I like my rule changes and as much as *I* think they add to the game, I'm sure a lot of people would find them unnecessarily complicated. I mean, if you're playing to quickly level up a character and kill Demon Lords and Arch Devils, why are you going to care about your character's childhood?
I guess the point I'm belaboring here is that if you look at ANY AD&D rule (first edition, remember) it's going to seem simplistic and underdeveloped, but it's supposed to be that way. Where it goes from there...is up to the DM.
It IS the longest lived, most popular RPG in the world, afterall. They musta done something right!
Gamaworld? I don't see anybody working on a revival.
Twilight 2000? (Hey! It's 2001!) No action there.
Car Wars? Why isn't somebody bringing that one back!? (It was a LOT of fun!)
But D&D is alive and doing well......
