Spell-ing it out?

TLDR: the simplest expression of a spell may be the most fun in play and engender the most creativity.

For your consideration, five iterations of one of the most basic of all D&D spells, by edition (skipping over a few):

Light: A spell to cast light in a circle 3” [30'] in diameter, not equal to full daylight. It lasts for a number of turns equal to 6 + the number of levels of the user; thus, a 7th-level Magic-User would cast the spell for 13 turns. 

[Oe Men & Magic, WotC collector's edition "reprint"]

This is our baseline. As far as I can tell it is faithful to the '76 Whitebox edition. I am trying to find an earlier scan.

Light*     Range 120' / Duration 12 turns
This spell casts light in a circle, 30' in diameter. It is bright enough to read by, but not equal to full daylight. It may be cast on an object. The light may be cast at a creature's eyes. The creature may make a saving throw, but if it fails, the victim will be blinded for 12 turns. In the D&D BASIC rules, a blinded creature may not attack.
* Reversible
[Moldvay/Cook Basic]

The spell gains a fixed duration, range, and some adjudication text because somebody decided to cast it "on" a creature's eyes and some GM allowed it. Note that the monster gets a saving throw. Also, it's now reversible. 

Light (Alteration) Reversible 
Level: 1   /   Components: V,S
Range: 12"   /   Casting Time: 4 segments
Duration: 6 turns + 1 turn/level   /   Saving Throw: None
Area of Effect: 2" radius globe
Explanation/Description: This spell causes excitation of molecules so as to make them brightly luminous. The light thus caused is equal to torch light in brightness, but its sphere is limited to 4” in diameter. It lasts for the duration indicated (7 turns at 1st experience level, 8at 2nd, 9at 3rd. etc.) or until the caster utters a word to extinguish the light. The light spell is reversible, causing darkness in the same area and under the same conditions, except the blackness persists for only one-half the duration that light would last. If this spell is cast upon a creature, the applicable magic resistance and saving throw dice rolls must be made. Success indicates that the spell affects the area immediately behind the creature, rather than the creature itself. In all other cases, the spell takes effect where the caster directs as long as he or she has a line of sight or unobstructed path for the spell; light can spring from air, rock, metal, wood, or almost any similar substance.
[AD&D PHB]

The spell now has a school and components, the duration is a level-dependent length, and the area is increased to a 40' diameter (assuming a 1":10' grid square). The spell gets a physics justification, and the brightness is characterized more specifically as torch-like. Details on the reversible version are given (and vary in duration). Magic resistance is mentioned, and there is some text about what happens if the target resists or saves vs. the spell.

Light     Evocation [Light]
Level: Brd 0, Clr 0, Drd 0, Sor/Wiz 0
Components: V, M/DF
Casting time: 1 standard action
Range: Touch
Target: Object touched
Duration: 10 min./level (D)
Saving Throw: None
Spell Resistance: No
This spell causes an object to glow like a torch, shedding bright light in a 20-foot radius (and dim light for an additional 20 feet) from the point you touch. The effect is immobile, but it can be cast on a movable object. Light taken into an area of magical darkness does not function.
A light spell (one with the light descriptor) counters and dispels a darkness spell (one with the darkness descriptor) of an equal or lower level.
Arcane Material Component: A firefly or a piece of phosphorescent moss.
[D&D 3.5, Online SRD]

The spell school is changed, and it gets a clerical domain. Components are expanded and specified. Range is reduce to touch, duration is still level-specific but simplified, and the spell is no longer reversible but instead "counters" spells of its opposite. Note that it's a lot harder to tag an enemy's eyes with Light now! 

Light     Evocation cantrip
Casting Time: 1 action
Range: Touch
Components: V, M (a firefly or phosphorescent moss)
Duration: 1 hour
You touch one object that is no larger than 10 feet in any dimension. Until the spell ends, the object sheds bright light in a 20-foot radius and dim light for an additional 20 feet. The light can be colored as you like. Completely covering the object with something opaque blocks the light. The spell ends if you cast it again or dismiss it as an action.
If you target an object held or worn by a hostile creature, that creature must succeed on a Dexterity saving throw to avoid the spell.
[5e PHB]

Light is leveled-down to an at-will cantrip (probably happened in 4e, actually), duration is fixed, and a Dex save is included for unwilling targets. So it's even harder to tag an enemy; you must first touch them and then hope they fail their Dex test? Or, perhaps there is no longer a touch attack roll, you just do it and then they try to dodge it. Yeah, probably that; I'm not a 5e expert.

So, I ask you, did the spell get "better" along the way?

I believe this progression is an illustration of the attempt to systematize all the common aspects of the game – to replace GM rulings with set rules. There is good and bad in that.

By spelling things out, the player experience is possibly more consistent from session to session and table to table. Also, the player has the fairly complete knowledge of how the spell works, possibly making work lighter for the GM (unless the player mis-remembers, and the GM has to correct the effects).

However, spelling it out also constrains the use of the spell. The more words devoted to the exact behavior, targeting, etc. of the spell, the narrower its usage becomes. I think it's safe to say that the latter spell descriptions rule out certain things. The phrase "one object that is no larger than 10 feet in any dimension" suggests that the spell has to be cast on an object – not living tissue like an enemy's eyes (reinforced by "if you target an object held or worn by a hostile creature") and it can't just emanate from you. This, very clear picture of how Light works – down to letting the caster choose the color – shuts out other choices that might be made for flavor or utility. What if I wanted to use a jar of fireflies as a component? Or cast the light on my palm so I could open and close my fist to send morse-code like signals? Maybe I wanted a halo around my head so I could look angelic.  

For fun, here are two more descriptions of light, one from a streamlined take on the old school rules, The Black Hack, and one from a Oe retroclone, Delving Deeper. To my way of thinking, the brevity of these entries is fantastic! 

Light: Creates dim light from a Nearby spot or object that lasts for Ud8 Minutes.
[The Black Hack 2e, "Ud" references the usage die mechanic.]

Light (reversible, duration: 12 turns, range: 120ft) Causes an object to shine as brightly as a torch, illuminating a 15ft radius. The reverse, darkness, creates a sphere of impenetrable darkness with a 15ft radius. [Delving Deeper v3, Vol. 1]



* Froth of the Thought Eater Podcast has suggested the spell summary in D&D 3.5 to be an excellent resource. There we have this gem: "Light: Object shines like a torch."