This illustrates what I mean, I think. A GM "training" his players in how he wants them to play reminds me of a person trying to "change" his significant other after they've started dating. Obviously it's not such serious business, but I think there's a real similarity here.
If a GM thinks his players would really enjoy puzzle solving and exploration, but just need to be drawn out of their shells a bit, that's one thing. But if his players really just enjoy NPC interaction and combat like Mal, or even if they want nothing but combat and powergaming, there's nothing at all inferior about their preferences, and there's no point in trying to "train" them out of what they enjoy. If A GM just really doesn't enjoy GMing the kind of game his players want to play, then he can honestly and nonjudgmentally tell them that he'd like to step down after next week's session.
Nah.
A GM "trains" his players as to the expectations of the campaign.
Is it worthwhile to talk to NPCs? The GM should demonstrate that this is so
before the wholesale slaughter begins.
Is there a benefit to/expectation of mercy? Again, the GM should demonstrate that this is so
before the wholesale slaughter begins.
Do the PCs have to talk to NPCs or show mercy? No. But they might miss things if they do not.
As long as the GM has players who want to play his game, he is justified in running any game he wants.
As long as a player is still welcome in a game, he is justified in running his character any way he wants.
A wise GM doesn't wait until every player is gone before considering his game; a wise player doesn't wait until he is booted from every game before he considers his playing.
If Bob is GMing, and Marcy and Joe want a different game, Bob absolutely does not need to "step down"; he can keep running a game for Sue and John. If Marcy then runs a game more like what she and Joe want, perhaps Bob, Sue, and/or John will also want to play in that game.
If, for some reason, Sue and John can only play in one game, then either Bob's or Marcy's gets them, depending upon which is closer to what Sue and John want.
The only reason Bob should "step down" is because he is tired of GMing.
If your players sit around saying they don't know what to do, you have failed as a GM.
Either the scenario and players lack immediate goals and motivations or you're not running the game they want to play.
This is no more, or less, true if reversed:
If your players sit around saying they don't know what to do, they have failed as players.
Either they lack immediate goals and motivations, or they're not choosing to play in the game they want to play.
Maybe the scenario sucks ("You're on a flat featureless plane with nothing to do.").
Maybe the players suck ("Can't you just tell us what to do?")
Or maybe the players simply have no experience with rpgs run so as to allow and expect them to make real choices. IMHO, and IME, this third is by far the most common cause. And, IMHO and IME, most players truly enjoy a game that allows and expects them to make real choices, assuming that it is run well. In fact, I would go so far as to say that I have never, ever, had a problem filling a table in this manner....my problem has always been the opposite. At what point do you start turning players away?
RC