To me the low point of fluff was 3.X, the high point of fluff 4e (i.e. it had the fluff I care about) and 5e has kept a lot but not all of the good 4e fluff.
The 3.5 Fireball spell specifies:
A fireball spell is an explosion of flame that detonates with a low roar and deals 1d6 points of fire damage per caster level (maximum 10d6) to every creature within the area. Unattended objects also take this damage. The explosion creates almost no pressure.
You point your finger and determine the range (distance and height) at which the fireball is to burst. A glowing, pea-sized bead streaks from the pointing digit and, unless it impacts upon a material body or solid barrier prior to attaining the prescribed range, blossoms into the fireball at that point. (An early impact results in an early detonation.) If you attempt to send the bead through a narrow passage, such as through an arrow slit, you must “hit” the opening with a ranged touch attack, or else the bead strikes the barrier and detonates prematurely.
The fireball sets fire to combustibles and damages objects in the area. It can melt metals with low melting points, such as lead, gold, copper, silver, and bronze. If the damage caused to an interposing barrier shatters or breaks through it, the fireball may continue beyond the barrier if the area permits; otherwise it stops at the barrier just as any other spell effect does.
Why is this the low point of fluff?
Because it makes no physical sense. In specific Copper (one of the listed metals) melts at 1084°C (1983°F). That both gives me a minimum temperature of the fireball and a minimum transfer of heat - and that's literally hotter than the furnaces in many crematoria. And that the heat is on the copper long enough to melt it. Here's someone melting a small amount copper with a blowtorch; it doesn't just take sustained heat but duration to transfer it; this is the sort of energy the fireball is transferring.
That sort of fluff both reads to me as if someone watched a Bugs Bunny cartoon and wrote down the effects and said that they always happened. The fluff makes the world a lot
less coherent and consistent.
Meanwhile 4e was the high point. But 5e keeps much of it. Let's compare the
3.5 Ray of Frost to
the 5e one. What's the difference? 3.5 Ray of Frost just does "blue damage" as opposed to the "red damage" done by fireball and there is little meaningful difference in the game world beyond that. Meanwhile, following in the footsteps of 4e, the 5e Ray of Frost also adds
"and its speed is reduced by 10 feet until the start of your next turn". It has an actual meaningfully different impact on the world and on the target.
One place where 4e was vastly better (and never mind I prefer 4e rituals to either spells or 5e rituals - but this is a worldbuilding choice) is that rather than just resistances and immunities 4e had reactions and consequences; effects that triggered when you hit foes with the wrong or right damage types that weren't just more or less damage. And the reactions and different movement meant that the characters
moved differently (5e keeps
some of that with Legendary Actions rather than just having generic claw-claw-bite-wing buffet-tail whip attacks but it's not a patch on the sheer physical force of instinctive actions)
Meanwhile the bit about "pointing and a pea shaped ball of fire" or "throwing a ball of fire"? I
actively do not want that specified. More accurately if I have a character who spits fire or shoots fire out of their eyes what's the problem with that. It's fluff, sure, but not something I really want. (I really
really don't understand why Cone of Cold needs to come out of my hands and not be a breath weapon - and Cone of Cold even in 5e is very much a "blue damage" spell with little meaningful difference from a fire spell).