I don't intend for this thread to discuss whether having every fight be a nova (i.e. PCs expend all of their most powerful abilities) is necessarily good or bad. Rather, I want to talk about what consequences and consideration should be taken into account ASSUMING that every fight is going to be a nova.
Should every challenge be set to deadly? Can we make adjustments to how numbers of enemies impact that difficulty? What does a nova set piece look like that is different than a "standard" set piece?
Other thoughts and considerations?
More spells available for non-combat use. Teleports, Pass without Trace spell rather than stealth skill, Levitate or Fly rather than climbing, divination spells rather than investigating etc.What about beyond the immediate tactical concerns? How does this idea affect the campaign broadly?
I think there are a number of models that might lend themselves toward the nova game. PCs that are explicitly a special strike force, for example, or are undergoing long term travel that only allows for isolated combat encounters. What else?
That would have a similar effect, yes. With all the associated risks and impact on party composition and player enjoyment.It occurred to me that another way to do this if you still wanted that multiple fight experience from a storytelling perspective would be to just say "all PCs gain the benefits of a long rest at the end of every encounter." That way you could still have a dungeon romp -- it just wouldn't be about resource management.
I'm not sure I understand how this is relevant. They still start the fight with max hit points, and have all of their spells. How does not having spent any hit dice impact the situation?No HD-based healing possible. This would normally occur in the two short rests of the standard adventuring day and mean that the party can recover HP without spells. Without these, the party are operating off roughly half of the HP they would have over the course of the day.
Shirt rest classes like Monk & warlock can do quite well with nova>rest>repeat. The simple fact that fitting in a one hour short rest is almost always narratively easier to justify and harder to narratively block with any consistency compared to an eight hour long rest. The result is much like an out of control 3.x CoDzills the gm is not counterbalancing with magic items & such for other players.One of the issues with making every fight a nova is the balance between classes. Some classes have much more nova potential, but it's tied up in limited resources that means that they have a strictly limited (often 1) "nova encounters" per long rest. Other classes, especially at-will classes or short-rest classes, explicitly can't bring as much in a single nova battle, but would be balanced over multiple battles per day.
Basically, the varying recovery models of the different classes in 5e are not compatible with the concept of every battle being a nova. Other RPGs, including D&D 4e (pre-essentials) where everyone has the same resources, could do it.
It depends on how you are creating the encounter. If you are just making a single deadly+ encounter by eyeball then it isn't relevant.I'm not sure I understand how this is relevant. They still start the fight with max hit points, and have all of their spells. How does not having spent any hit dice impact the situation?
No, the challenge should be appropriate for the setting, the circumstances or the result of the players actions/decisionsShould every challenge be set to deadly? Can we make adjustments to how numbers of enemies impact that difficulty? What does a nova set piece look like that is different than a "standard" set piece?
Other thoughts and considerations?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.