Can you please give me an example where the 4e Tier system has helped you decide on an action and where you foresee same action in a system like D&DNext (at least in the playtest) impedes such action due to a no Tier system?
Yes. Here are the links, to a
paragon example and an
epic example.
In the paragon example, the dwarven thrower artefact Whelm was being reforged as Overwhelm - a mordenkrad. To help with the reforging (in mechanical terms, in order to try and bring the skill challenge to a successful resolution) the player declared that he wanted his PC (a mid-paragon fighter/cleric of Moradin) to put his hands into the forge and hold the hammer steady so the artificers could grab it with their tongs. (Mechanically, this was resolved as an Endurance check.)
Page 28 of the PHB says this about paragon tier:
In the paragon tier, your character is a shining example of heroism, set well apart from the masses. . . You are able to travel more quickly from place to place, perhaps on a hippogriff mount or using a spell to grant your party flight. In combat, you might fly or even teleport short distances. Death becomes a surmountable obstacle, and the fate of a nation or even the world might hang in the balance as you undertake momentous quests.
Individual paragon paths add further detail to this sense of what paragon PCs are capable of
in the fiction. For instance, one of the PCs in my game is a Demonskin Adpet. This means that he is capable of crafting magical robes out of demon skins that let him channel power from the Abyss against the wills of the demon princes who live there.
This all helps to make it clear that a paragon dwarven fighter/cleric is exactly the sort of person who probably can shove his/her hands into a dwarven forge and hold a magical weapon steady while the artificers grab it with their tongs.
In the epic example, one of the action declarations that had to be resolved was whether or not a mid-epic character can use an Undead Ward to sever Vecna's connection with his eye. Another one that had to be resolved was whether or not the same character can use an Adjure ritual to manipulate a god's binding of a demon.
Page 29 of the PHB says this about epic tier:
In the epic tier, your character’s capabilities are truly superheroic. . . You travel across nations in the blink of an eye, and your whole party might take to the air in combat. The success or failure of your adventures has far-reaching consequences, possibly determining the fate of millions in this world and even planes beyond. You navigate otherworldly realms and explore neverbefore-seen caverns of wonder . . .
Individual epic destinies add further detail to this sense of what epic PCs are capable of in the fiction. For instance, one of the PCs in my game is a demigod. Another is a Marshall of Letherna, meaning that he is a knight commander in service to the Raven Queen. Another is an emergent primordial. These are the sorts of characters who can use their own magic to manipulate the magic of the gods; hence both those action declarations are feasible.
These relatively clearly expressed features of the different tiers are also known to the players, of course, and so help give them a sense of what is or isn't feasible. For instance, it's obvious that a paragon fighter is not limited, in terms of physical capabilities, to what an ordinary human being might do. And it's obvious that epic PCs are peers of the gods, or at least well on their way to being such.
pemerton said:
D&Dnext relies upon bounded accuracy plus the GM's sense of the "objective" ingame situation to assign difficulties that are appropriate for the game.
How is this different to 4e?
4e uses level-appropriate DCs. The basic assumption is that the GM will set DCs and use damage expressions that are appropriate, and then narrate the fiction appropriately for those DCs. This is illustrated, for instance, on p 64 of the 4e DMG, which has a chart of DCs by door type, and then advises
Some of the examples below show DCs for breaking down doors or opening locks, and also show the level at which a character should be able to break down the door with a Strength check of moderate difficulty. Thus, that level is a good rule of thumb for dungeon design. Don’t put an iron door in a dungeon designed for 10th-level characters unless you intend it to be difficult for them to break through.
Another example is found on p 44:
The table below [which is entitled "Fall Severity by Character Level"]l classifies the distances of falls according to their severity by character level. A painful fall does significant damage to characters of the indicated levels, but shouldn’t kill a character who’s not yet bloodied. A perilous fall might kill a bloodied character, and could leave even a character at full health bloodied. A deadly fall could kill a fragile character, will probably make a character bloodied, and threatens significant harm even to a character who has more hit points than any of his companions.
A consequence of this is that DCs don't provide any genuine information about what is or isn't feasible for the PCs. That has already been decided at the "is this action declaration permissible?" phase, and is decided by reference to the mutually understood fiction. DCs are then set on a level-appropriate basis, and serve a rationing and pacing function. But there are no "objective" DCs such that you can say (for instance) the DC of holding an artefact steady in a dwarven forge is X, and then (for instance) aspire to building a 8th level PC whose Endurance skill bonus is so high that s/he can aspire to do that even though s/he is not yet paragon tier.
D&Dnext seems to me - at least from the playtest documents - to be much closer to 3E in its approach to DC-setting. The DC of any given task is what it is, and is intended as an objective measure of ingame difficulty. One upshot of that is, because we can't conceive of any 1st level PC possibly holding an artefact steady in a forge while the artificers grab it with their tongs, this is never likely to be a viable action declaration even for a much higher level character - because there is no DC we can set that makes it relatively viable for that PC yet impossible for the 1st level one. Hence, my feeling is that a player who wants his/her PC to do something like that won't do it by improvising with the Endurance skill (or CON checks) - s/he will use Potions of Fire Resistance or some similar, unequivocal, rules-driven solution.
Hence my view that D&Dnext may produce freewheeling GMs, but at least for me and those with whom I play, is less likely to produce free-wheeling players.