Quasqueton said:
Player: "I move 4 squares over and here cast fireball centered on this intersection."
DM: "You provoke an attack of opportunity from the warrior."
Player: "Crap, then I don't want to move like that. I'll stay put and cast."
DM: "You provoke a casting attack of opportunity from the warrior."
Player: "Oh, I can take a 5' step before I cast, right? Then I'll move over there."
DM: "You can't take a 5' step and move in the same turn."
Player: "Damn. Well..."
Here's my version of this:
FIRST SESSION
Player 1: "I move 4 squares over and here cast fireball centered on this intersection."
DM: -rolls dice- "The warrior lashes out as you move away, catching you on the shoulder. 7 damage. You're still up, right? Okay, cast your spell."
Player 1: "B... but, I wouldn't have moved -"
DM (sternly): "Roll them d6s.
Fireball is on its way. Next time, be ready."
SECOND SESSION
Player 1: "Give me a minute to figure out what I'm going to do. I don't want to take an AoO."
DM: -starts stopwatch at 30 seconds-
Player 1: "Um... um..."
DM: "Time's up. What do you do?"
Player 1: "Uh... I hit the orc with my staff."
DM: "Roll damage."
THIRD SESSION
Player 1: "I cast a
fireball on the orcs."
DM: "Roll 'em. Player 2?"
Player 2: "I don't have many hp left. I'll strike at the chieftain's neck and try to lop his head clean off! That ought to scare them!"
DM: "Sounds good. Would you like an action point with your power attack?"
Player 2: "To hit."
Player 2: -rolls- "14... 18 with the action point! That hits, right? 29 damage."
DM: "Your blade bites deep into the chieftain's bull neck. He stumbles back, working his jaw as though to howl his rage. All he manages is a gargled cough as blood cascades from the dreadful wound. He crumples, dead or nearly so. You earn back two action points."
Player 2: "Wicked."
FOURTH SESSION
Player 1: "Can I add an action point to my
magic missile damage?"
DM: "How are you getting that extra oomph?"
Player 1: "Huh?"
DM: "Describe how you're casting the spell."
Player 1: "I... uh..."
DM: "Roll damage; you can't use an action point."
FIFTH SESSION
Player 1: "I'll conjure a
fireball. I'll try to lob it right at the middle of the bugbear siege tower, on top. This square right here."
DM: "Good idea. Would you like to add an action point to damage or saves?"
Player 1: "Bugbears are tough; damage."
DM: -rolls saves- "Roll."
Player 1: "45 damage with the action point."
DM: "Your burst of flame explodes atop the siege tower. Screaming bugbears, their armored paws swatting at their flame-swathed bodies, tumble off in their rage and pain. The tower itself blazes like a cyclopean torch. Earn back two action points."
Our theoretical GM (certainly not anyone I know, or myself, or anything
) raises the bar for the tactical and descriptive prerequisites over time. Eventually, the players become accustomed to vivid description, carefully observing the situation on OTHER players' turns, and making snap judgements.