I think you have to have the ability to define your charactor through means of story. Alot of RPGs out there do not allow this and IMO are not true RPGs. If there is a linear series of quests and all the dialogue (your charactor included) is pre-written, then it is not a true RPG. So most of the RPGs in the 80s and 90s were not really RPGs IMO.
As you stated Bismark, you also define ytour charactor through a skill/stat system as honestly it is generally the best way using one of those 2. But another important part (very important really) is your ability to define your charactor's role in the world. That being said, having the story be predetermined no matter the player's actions then the role play bit is pretty much gone. FOr instance if I walk into a bar in a game and just be a total dickhead to the bartender every time I talk with him and everytime I come in he welcomes me with the same warm smile that he always has since the first time I met him, then my actions aren't really effecting the world and it really isn't role play. If the player is never given a choice on anything, you really haven't made an RPG.
As you stated Bismark, you also define ytour charactor through a skill/stat system as honestly it is generally the best way using one of those 2. But another important part (very important really) is your ability to define your charactor's role in the world. That being said, having the story be predetermined no matter the player's actions then the role play bit is pretty much gone. FOr instance if I walk into a bar in a game and just be a total dickhead to the bartender every time I talk with him and everytime I come in he welcomes me with the same warm smile that he always has since the first time I met him, then my actions aren't really effecting the world and it really isn't role play. If the player is never given a choice on anything, you really haven't made an RPG.