I no longer talk of games in terms of "realistic", those that crunch it out tend to end up unplayable. What I prefer is "believability": the game world reacts in a logical manner according to its rules.
Actually, the 3rd edition rules were surprisingly realistic, as long as you realized that although they supported 1st through 20th levels in actual fact 5th to 6th level represented the peak of normal human capability. As in Conan or Aragorn would be 5th or 6th level characters. That you could go on to level your characters much higher than that, well into the super-human range, doesn't mean the rules themselves were necessarily unrealistic.
But I agree with your point that 'realistic' as a term to describe any fantasy role-playing system is useless. I think that the more appropriate distinction is whether the mechanics are associated or disassociated with player decisions. In other words, how much of what your character does is specifically associated with decisions you as a player make, and how much of it is simply resolved by an abstract dice roll. In 1st edition, with combat rounds lasting 10 minutes according to some interpretations of the rules, almost the entire combat is a disassociated mechanic. Your 1 attack and damage roll represent a whole series of actual game-world maneuvers, faints, thrusts, parries, slashes, and so on. On the other hand, trap detection and disarming was almost 100% associated. Your character would not do anything you as a player did not tell him to do, so if you didn't know, in real life as a player, how to detect and disarm a trap, or where to search for something hidden in a room, the character wouldn't know either.
It's interesting to me how D&D has evolved to make combat more and more associated, with all different kinds of feats or powers or techniques or what-have-you with specific rules, modifiers, and mechanics designed to make combat an exercise in tactical system mastery... and yet at the same time has dissassociated room searching and trap detecting and disarming. Whereas before, battling the goblin was a simple matter of rolling a couple die a few times and letting the DM provide fluff details, now battling the goblin is broken down into 5 second rounds with pages worth of options for unique attack maneuvers. Now, to find and disarm a trap, the rogue makes his search check and then his disarm check, and the DM fills in the fluff details. Before, finding the trap meant you had to interrogate the DM on the details of every wall, floor, and ceiling, prod ahead with your ten foot pole, spill water on the ground, throw out chalk powder, check for scuff marks or strange breezes, and any of a million other things that were clues to a nearby trap or secret entrance or hidden treasure.
To me, it's all fun. I favor associated mechanics in all cases, whether its combat or exploration, or even role-playing. Resolving any complex situation with a single dice roll that's meant to account for a whole series of possible actions separates a player from their character and takes me out of the moment.
Are you being serious? If 5th to 6th level represents the peak of "reality" then some of us should be able to throw a fireball by now. 
