I have practiced the martial arts for some time. I started in Chinese Kung Fu, several different styles off and on until I hit my late 30's. It was about three years in that I realized one of the difficulties facing the kung fu community. Lineage. Many teachers simply did not know how to apply the arts they taught in any practical way. They would often explain that the applications were embedded in the forms; and all you had to do was practice them continually and the applications would become apparent. Others would show an application or two, usually very unrealistically and explain that there were thousands of variations on this technique that would become apparent over time. I became frustrated with this and drifted to other arts. Then I found Kenpo. Kenpo was a great art. But it was actually in decline.
Kenpo had been created by Ed Parker in the early 70's , and he was constantly revising the art and the manner in which it was taught. He gained several devoted high level students that began the spread of Kenpo throughout the Americas. At that time Kenpo was a living and breathing art reaching new students every day. Until Ed Parker died suddenly from a heart attack in his 50's. The Kenpo world was in shock. He had named no clear successor but left a half a dozen high level black belts with strong personalities behind. It wouldn't take a statistician to predict what was about to happen. Kenpo splintered first into three then six and a dozen different Kenpo variations and organizations. Today the Kenpo world is shattered. Her roots withering from branches grown too far from the source and indeed cut off from the source altogether. The most commercially succesful branches have left Kenpo altogether and begun entirely new arts. I have practiced in many schools, and there is little depth in them. They are like plastic copies of what has come before. It is the same thing I felt with some Kung Fu school separated from their roots by thousands of years. Kenpo is dying too. If it's not dead already.
I can't help but feel the same thing happening to gaming today. I mean there are lots of people gaming, just like there are lots of people practicing in dojos all over the world. But what are they doing really? What are they playing? Are they plastic imitations of the originals or some new branch that has broken off of the staff? I'm at a loss to tell you the truth. It may be just me. But I can't seem to find the magic--anywhere. The clones don't quite do it, the new commercial offerings don't quite do it. They get close, but they are missing some ineffable quality that the originals possessed. At least for me.
These news games are excellent creations, I don't want to down them. Just like some very successful Kenpo schools teaching a new twist on the old. But they aren't "it". They are ultimately different. Some might say that they are close enough, or that they are even better. But I don't see it. I don't see it and I don't feel it. In my opinion the only reason one would even play a retro clone would be that they are better than the originals. Otherwise you might as well play the originals.
Now, some might be confused by this. Just recently I recommended that those that want to play 0e play S&W instead of the originals. But you know what? I'm not even qualified to make that statement. I have never played 0e and I never played B/X. I am a strict AD&D 1e man. That's what I played and that's what I know. I owned B/X and I played some the modules, but I tweaked them for AD&D. Why play B/X, I reasoned, when AD&D was available? (That is strictly opinion not a commentary). So the only clone I feel inclined to judge is OSRIC and maybe LL AEC. LL AEC is just not advanced. It's more like Basic on steroids. And we all know how I feel about OSRIC.
Variants are really different games altogether. They make changes to the original idealogies and add their own twists. So unless you are looking for a new game they aren't an adequate replacement for the originals either. C&C comes really close to AD&D feel with the exception of the d20 mechanic and the Siege Engine. It's a light system however, and so they play differently in many regards. And they certainly don't have that baroque spirit enshrined in the original AD&D.