instead of a referee, or simply referencing the rulebook, for adjudication of a certain scenario as you would in a war-game, you had a new sort of player - the DM, who assumed the roles of dungeon creator, referee and rules interpreter and adjudicator, NPC and monster actor, etc.
There are different categories of judgement call and adjudication.The idea that the DM isn't supposed to make any judgement calls or changes once the game has started is pretty extreme.
Here's one scenario: a PC is disarmed. The GM has previously described the room as containing an iron candelabra sitting on the altar. The player of the disarmed PC declares, "I pick up the canelabra to use as club!"
This sort of action declaration is pretty much paradigmatic for a RPG - it is a single-character action declaration (rather than a declaration at the unit or commander level, as in a traditional wargame); and it involves engaging with the fiction - ie the candelabra on the altar isn't just flavoursome gloss on the framing of the game state (contrast, say, the illustration on a Magic card, or the backstory and flavour text of a boardgame like Forbidden Island). In a RPG, engaging the fiction is always a permissible move.
Traditionally, it is the GM's job to decide how to mechanically implement the PC's wiedling of a candelabra eg is s/he considered proficient with it? How much damage does it do? Page 47 of the 5E Basic PDF even comes out and says as much:
In many cases, an improvised weapon is similar to an actual weapon and can be treated as such. For example, a table leg is akin to a club. At the DM’s option, a character proficient with a weapon can use a similar object as if it were that weapon and use his or her proficiency bonus.
I wonder how [MENTION=54380]shoak1[/MENTION] prefers to handle this sort of situation. GM decision? Table consensus? (Those two can often blur together, of course.) Table vote? Something else? Maybe there's a gentelmen's agreement at the table not to use improvised weapons?
But there are other sorts of judgement call or adjudication that have a much bigger impact on gameplay, and I'm guessing these are the ones shoak1 is more concerned with - for instance, whether encountered creatures are hostile or friendly; whether they pursue fleeing PCs or let them go; etc.
In his DMG, Gygax provides a whole suite of subsystems intended to take these decisions out of the GM's hands, so that the GM is not the one deciding (in effect) the outcome of the situations the PCs find themselves in. Thus, there are reaction dice to determine whether or not NPCs and monsters attack.
And there are very elaborate rules for pursuit (DMG p 63):
Whether or not the opponent party will follow in pursuit of the fleeing party depends on the following factors:
1. What you, the Dungeon Master, have stated in your key concerning the party, if applicable. This is first and foremost in ALL cases.
2. What the stated characteristics of the creature(s) involved are. That is, if player characters, do they say they will pursue, or if monsters, does their description say that they will always seek to pursue?
3. Obvious deterrents to pursuit, such as a pool of flaming oil, a secured portal, etc. will modify monster behavior accordingly.
4. Fleeing party behavior and/or possessions noted by the opponent party will modify pursuit desire.
5. Relative speed will cause the pursuing party to cease fruitless chase if they are obviously being outdistanced (except if the pursuers are player characters who must state they are halting such chase).
6. Otherwise 50% of the time (d6, 1-3 = pursuit, 4-6 = break off pursuit).
1. What you, the Dungeon Master, have stated in your key concerning the party, if applicable. This is first and foremost in ALL cases.
2. What the stated characteristics of the creature(s) involved are. That is, if player characters, do they say they will pursue, or if monsters, does their description say that they will always seek to pursue?
3. Obvious deterrents to pursuit, such as a pool of flaming oil, a secured portal, etc. will modify monster behavior accordingly.
4. Fleeing party behavior and/or possessions noted by the opponent party will modify pursuit desire.
5. Relative speed will cause the pursuing party to cease fruitless chase if they are obviously being outdistanced (except if the pursuers are player characters who must state they are halting such chase).
6. Otherwise 50% of the time (d6, 1-3 = pursuit, 4-6 = break off pursuit).
There are also rules for the likelihoood of abandoning pursuit once started if the PCs throw food and/or loot to their pursuers.
This all seems intended to ameliorate or eliminate a certain sort of GM judgement call. It is consistent with the approach to play described by Lewis Pulsipher and posted not far upthread by shoak1.