I think its defintely true of spells. I play wizards/druids a lot when Im not DMing. Heres a comparison of a few wizard spells.
For me. The old way of writing spells made me want to curl up, find out what the spell does and imagine if my character would want to do that. The new way makes me feel think they are all basically the same and instead of doing the tedious math work to find out whats the "best" ill just take a build off of a forum and play that (actually thats a lie, I'd rather just not play).
I'm looking at the examples you provided and I've copied one of them below. I've colored the "fluff" yellow and the "crunch" red. I've left out the really "technical info" (e.g. casting time, duration, etc) - they read like this:
3e sleep
A sleep spell causes a magical slumber to come upon 4 Hit Dice of creatures.
Creatures with the fewest HD are affected first. Among creatures with equal HD, those who are closest to the spell’s point of origin are affected first. Hit Dice that are not sufficient to affect a creature are wasted.
Sleeping creatures are helpless. Slapping or wounding awakens an affected creature, but normal noise does not. Awakening a creature is a standard action (an application of the aid another action).
Sleep does not target unconscious creatures, constructs, or undead creatures.
Material Component
A pinch of fine sand, rose petals, or a live cricket.
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4e sleep
You exert your will against your foes, seeking to overwhelm them with a tide of magical weariness.
Hit: The target is slowed (save ends). If the target fails its first saving throw against this power, the target becomes unconscious (save ends).
Miss: The target is slowed (save ends).
It seems to me, that in this instance at least, 3e has more "rules language," but that rules language is not simply technical information (It doesn't exist solely as a "stat block") and less instances of discrete "fluff" (or prose, or whatever we call it). The 4e example seems very concise - nearly bordering terse (in my opinion). With the effects of the spell written in more technical terms (which is comprised of 4e specific jargon such as keywords, etc...) So, I'm wondering if it's not so much "prose" vs. "technical," but rather it's about representation and engagement.
I'm not arguing the language of one edition over another, but perhaps what is important is the "discourse" of the game. This involves written rules, jargon, the language of the game as it is played, the language used to describe how the game is played - essentially all linguistic elements that represent D&D and orient our understanding of what "D&D" is (like how a glass [the discourse] shapes water [our understanding of the game]). This needs to match player expectations, or at least is engaging/compelling enough that players can allow their expectations to be changed.
But, in any case, the representation (discourse) of D&D must be such that it is engaging - and that didn't seem to happen with a number of people when 4e arrived, because much of the traditional discourse of D&D changed. I'm not saying 4e
isn't D&D, but just that the discourse changed, and that change disoriented some players.
So, perhaps a task of 5e is to also reconstruct the discourse of D&D so that it reorients people to a more unified (or acceptable) representation of D&D.