Mark CMG
Creative Mountain Games
Having social skills in the game allows you to attract both types of players if you really think about it. A group with a lot of charismatic people at the table can choose to house rule social skills out and just go with role playing all those type encounters.
A group who has players with issues or who just don't want to mess with role playing have a rule that adjudicates how to handle it.
Some people have the natural ability to sell ice to Eskimos but most of us don't. A person with a high charisma represents that type of person I have only really seen one person at a gaming table who in real life represents that level of charisma.
I have a friend who is in a wheelchair from being born with spinal bifida in real life he could not swing a sword in combat or be an agile tumbling rogue yet the game allows him to play out his fantasy and no one ever has an issue with that but a shy person having the fantasy of being a fast talking bard or swashbuckler seems to cause some people to have issues.
A game that tries to be inclusive for different type of players and play styles is going to be more successful than one that excludes people.
You're very right that the designers of a game, any game, can choose to cater to more and more people by designing that game to include people who aren't as skilled at the type of game it is. It can do this in a number of manners. Most notably it can be designed to be the best game of its type and have optional rules that can be added to make it more receptive to additional players who might not be as skilled at that type of game or it can be designed to include all levels of players and allow skilled players to exclude parts of the design that are not necessary for a game of its type. The question becomes, which is its best design for a game of its type? Is the goal to be best designed as its type of game or to attract as many players as possible? Are the roleplaying aspects of a roleplaying game the fundamental concern of the game design to which the greater considerations are afforded, and optional rules included for those who aren't as skilled or interested in roleplaying included to attract a wider audience, or is the fundamental concern in attracting the wider audience with options on how to exclude aspects of the game for those who are skilled roleplayers? Is there a best way to design a roleplaying game regardless of who, or in what number, the roleplaying game will attract?
Remember, we're not talking about a game designed as a sword-swinging game or a tumbling game, it is being designed as a roleplaying game. Are the best designed rules of fencing designed so that someone who cannot fence well can fence with another skilled fencer? Are the best designed rules of gymnastics designed so that someone who cannot tumble can do well at gymnastics alongside a skilled gymnast? I think it's fair to say that each activity is designed to be the best of its type and if someone who cannot do it well wishes to take it up, then some additional modifications are made to accomodate the less skilled individual.
And lest this point get lost in the shuffle, a roleplaying game is best designed, IMO, when it includes aspects of both roleplaying and gaming, which is to say rolling dice and roleplaying playing a character. There are plenty of games where roleplaying is not a part of the game but we don't call them roleplaying games. This is also with the understanding that some mechanics are included in the roleplaying game for social skills. But to limit the roleplaying aspects, or make the roleplaying a non-factor in successfully playing the game, is simply taking the roleplaying out of the roleplaying game at a fundamental level.
By extension, I can include roleplaying aspects in many types of non-roleplaying games but if they are a non-factor in successfully playing those games then they are not roleplaying games. For instance, if I am playing a minatures wargame as acting commander of an army in pitched battle against another player's army and when I move the figure representing my general toward some portion of my troops to boost their morale factor I choose to shout, "Hold, soldiers! Do not falter!" it does not thereby become a roleplaying game because my roleplaying has no influence on the actual outcome of the game.
So, too, if I am playing chess and move my bishop to threaten the position of the opponent's queen and I opt to say, "Heed my bishop's warning and withdraw," in my most diplomatic tone, it has no meaningful bearing on the choice made by my opponent to withdraw, take my bishop with his queen, or move another piece and allow me the choice to take his queen, and therefore I have not turned chess into a roleplaying game by merely roleplaying in conjunction with my game turn.
If the roleplaying in a game has no bearing on the actual game then I would posit that the game I am playing is not a well designed roleplaying game but rather another type of game with roleplaying merely added on without the best roleplaying game design considerations in the fore.