Well guess what, I had my first experience of pen & paper RPG a few days ago. It was fun, and i would gladly do it again given the chance. But I don't think it translates well into a computer game.
Its just inherent in most gamers that they would rather rely on their own skill to beat a game, rather than luck. The classic video games which are mostly platformers and sidescrolling games don't have any dice rolls, its all about your own motor skills and hand-eye-coordination. I am no different, although I can accept a certain degree of randomness in games. But ultimately, I think most gamers would like to feel that they beat a game by their own ability, rather than dumb luck.
@Black Angel: Don't be so sore than turn-based combat is not popular, people nowadays only respect skill. There's good reason they aren't considered e-sports. The only one is played competitively is Pokemon, and even the pro players know luck plays a huge factor in it. You're being quite elitist in your opinions.
I say, RPGs are all about character skills, strengths and weaknesses. If you're playing a game that requires player's skill in combat, lockpicking, hacking, repairing, speech, crafting, medicine, etc, then it is not a RPG.
RPGs are all about player skill only on making and controlling your character, all the character's dealings with the world and people, creatures, situations, combat, etc should use the character's skills. That is the fundamental mechanic from RPGs, that is what all the P&P RPGs have in common and that is what all the first cRPGs also have in common.
You are playing the role of that character and interacting with the world using that character's skills and attributes. If a RPG does not do that, then you are not roleplaying that character... You are playing yourself... It is not the character who does things, it is the player and so it is not roleplaying, it is just playing.
The only player skills that RPGs use are mental, and that is why they used to be associated with "nerds" because it was more of a mental challenge than a physical one. You make your character and pick his strengths and weaknesses, then you try to survive and overcome the obstacles that the universe where that character exists throws at it, using his limitations and strengths.
If your character is dumb (lets say it has Intelligence of 1 in a Fallout game) and there is a complex puzzle in the world. The character would fail to do the puzzle even if the player is smart enough to see the solution for that puzzle and know how to do it, that is a roleplaying game.
Another example, if the character has maxed the lockpick skill, and would be able to unlock any "easy" lock with his eyes closed. But then the game still throws a lockpick mini game that the player has to play it and do it themselves, even if it is easier with maxed skill, if the player doesn't understand how the mini game works, of is distracted or something they might not be able to unlock it. That is not how the character would have done it, it is how the player does it.
People who only enjoy beating a game or challenges in a game using their skills (motor, reflex and other physical skills) do not really like RPGs.