Um, yeah. The DM has three jobs: Referee (rules-adjuster), Narrator (scene setter), and Loyal Opposition (monster runner). His job is to make sure all three of these things are in balance. He has the right to smack down those who use one area to break down another. If using the rules breaks either the setting of world (verisimilitude, if you will) or his ability to run encounters in a reasonable, challenging way, the DM has imperative to put on his referee hat and smack that rule down.
OK, well, of those three jobs, I simply disagree with the first in just about all instances of 'a roleplaying game'. The only thing any GM will achieve by unilaterally changing (or "adjusting") a rule is to break the game for the players who want any active role in the affair. The other two roles are fine - and there are other, lesser roles besides - but rather than do them by changing the rules to make them easy, I prefer to do them by (a) picking a decent rule set to start with and (b) knowing those rules and how they work.
What the characters are doing (climbing a wall, swinging a sword) is FLUFF...HOW you determine what they do is mechanics, and mechanics is what the players are doing (rolling dice, adding numbers, etc). (I think you meant characters not players, if so, we agree, if you truly mean players, then we do not)
We don't say "roll a d20 and add 5 to the number" and based on that result (say a 15) say "aha! you are climbing a wall!". We say "you are climbing a wall" then we "roll a d20 and add 5 to the number". The fluff comes first. The narrative comes first.
This is a roleplaying game. Players are assuming a role, a persona, and the dice (mechanics) are there to help determine what the persona can do,succeed or fail at, etc. in ways the player cannot. I cannot swing a sword effectively. But my persona can. Next, here are the mechanics that describe that fiction.
Ah, no - this isn't what I meant. I'll try to be clearer.
Yes, I do mean the
players, not the
characters; the characters don't actually 'do' anything, since they don't exist.
But I don't mean "what do they do" in the sense of rolling dice and so on; the 'activities' of "using the mechanics" and "engaging with the fiction" are just givens - they are the
way that the players do what they do, not the
essence of what they do.
By "what do the players do?" I mean what is their role in the overall activity; what decisions do they make that are theirs alone to make, and that comprise their contribution to the outcome. What bits of the whole, if you like, would make the whole outcome of "the roleplaying" impossible to achieve with the GM alone.
Some examples, for the purposes of illustration:
- The players are exploring the world that the GM has created through the medium of their character. Their goal is understanding and appreciation of the world that has been constructed.
- The players are trying to overcome the challenge set before them by the GM, be it a combat to win, a mystery to solve, an intrigue to navigate or a tower or tomb to rob.
- The players are the audience for the GM's epic tale, experiencing the tale through the medium of the experiences of the characters they have generated.
- The players are deciding on the theme and direction of the story in the game by means of defining their characters' "dramatic needs" and, in the role of their character, pursuing those needs.
- The players are selecting via in-character decisions their character's course through a matrix- or logic-diagram type situation created by the GM for them to (attempt to) navigate.
Many others are doubtless possible, and more than one may be mixed into any one game, but the ones desired will inform a great deal about the rules that would best be used. In a game where the players must overcome combat challenges as a core feature of "what the players do", for example, it is very desirable to have the combat abilities of the characters well balanced. In a game where the players are expected to explore specific aspects of an imaginary world without emphasis on overcoming challenges, not only is such balance far less necessary, but such features as character generation that results in characters related to the aspect of the world to be explored become important. Hence why, in Ars Magica, you don't generate characters that are serf peasants, or noble lords - you generate characters who are, or have dealings with, magi.
This is what I mean by "first you must consider what the players are intended to do". I mean, quite literally, what is occupying their thoughts as they play - what must they make decisions about that are entirely within their own purview (i.e. those where neither the GM nor the system tell them what decision to make)?