Yes. I think your criticism identifies a real distinction that is often missed when people talk about “good prose”: ease of reading is not always the same thing as effectiveness of reading.
There are theories of writing that push against your position, but I don't think they refute it. They are optimizing for a different purpose.
The strongest counterargument comes from plain-language/readability theory and, more broadly, the idea that prose should minimize cognitive load. In technical writing, journalism, instruction manuals, and especially material that must be processed quickly, sentence-level friction can interfere with comprehension. There is good reason to prefer familiar words, straightforward syntax, and predictable sentence structures in those contexts.
But you're describing almost the opposite objective. You want productive cognitive friction. The reader shouldn't have difficulty understanding the sentence, but the sentence should make them pause. That distinction is important.
There are literary traditions that deliberately do this. Defamiliarization, associated particularly with Viktor Shklovsky, argues that habitual perception becomes automatic and that art can make familiar things strange again by making perception itself more difficult. Similarly, close-reading traditions often value syntactic ambiguity, unusual diction, rhythm, and deliberate pacing precisely because they prevent the reader from simply consuming the text as information.
And your cadence point is particularly relevant to something written for a DM. You're not necessarily writing prose that should be silently skimmed. You're writing something that can function as a mental score for improvisation. The punctuation and sentence boundaries give the DM places to stop, look, absorb, and then reconstruct the scene in their own words.
So I would revise my previous approach considerably. I was trying to make the paragraph better behaved. You are deliberately making it resistant to being skimmed.
With that in mind, I'd make the following version:
"The corridor opens into a cavernous vault, imposing and uplifting, a chamber of concealed glory, with no apparent exits. The cracked and missing floor tiles must once have been laid out in colorful patterns, while the walls show traces of painted plaster, mostly eroded by time and damp, but still directing the eye upward to the domed ceiling. The ceiling itself is covered with countless years of grime, masking all but hints of the frescoes beneath it. Footsteps and conversation echo loudly throughout the room and down the corridor, making even ordinary speech seem somehow out of place."
There are some very deliberate things happening here.
I kept your first sentence almost intact. I think that's important. “Imposing and uplifting” is slightly paradoxical, and “a chamber of concealed glory” is not the sort of phrase I'd want to smooth away. It makes the reader stop and ask what, exactly, is being concealed.
I retained “directing the eye upward.” It's slightly formal and somewhat unusual. Good. “Drawing the eye upward” would be smoother, but I don't think smoother is necessarily better here.
I retained “countless years of grime.” You specifically want language that makes the reader linger, and this is an example of a phrase that does that. “Centuries of grime” is more idiomatic and more precise, but also more disposable. “Countless years” makes the reader momentarily contemplate the duration rather than merely register “old.”
And I changed only the final clause:
“suggesting hushed tones as the best option for privacy”
to
“making even ordinary speech seem somehow out of place.”
The latter doesn't tell the DM why they should have the players whisper. It gives the DM a sensory/emotional instruction from which they can construct the description themselves. It also doesn't identify the room as religious. The players get the echoes; they get the verticality; they get the faded decoration; they get the unexplained sense that this was once something grand. They get to assemble the hypothesis.
There's another possibility that I actually like even better if you want to preserve more of the original's slightly archaic, evocative quality:
The corridor opens into a cavernous vault, imposing and uplifting, a chamber of concealed glory, with no apparent exits. The cracked and missing floor tiles must once have been laid out in colorful patterns, while the walls show traces of painted plaster, mostly eroded by time and damp, but still directing the eye upward to the domed ceiling. The ceiling itself is covered with countless years of grime, masking all but hints of the frescoes beneath it. Footsteps and conversation echo loudly throughout the room and down the corridor, suggesting that hushed tones might be more appropriate here.
I prefer “might be more appropriate here” to “the best option for privacy.” It's intentionally understated. It doesn't tell the DM “this is a church.” It doesn't tell the players “this is a church.” It merely gives the DM the final piece of the intended atmosphere.
And there's a subtle advantage to retaining “suggesting.” The room isn't actually telling anyone to be quiet. The acoustics suggest it. That's exactly the kind of distinction that lets the DM turn the paragraph into their own description rather than simply reproduce it.
In fact, after hearing your rationale, I think I'd go one step further: I wouldn't try to eliminate every awkward or unusual construction in the original. Some of those constructions may be doing exactly what you want. If the prose occasionally makes the DM stop and think “What does that actually mean?”, that's potentially a feature rather than a defect—provided the underlying image becomes clearer rather than murkier.
The goal isn't frictionless prose. It's friction at the points where you want attention, and fluency at the points where you don't. That's a much more interesting editorial principle, and I think it's particularly well suited to this kind of DM-facing writing.
If you want, I can also take the original sentence by sentence and distinguish which awkwardnesses are productive and which are merely accidental, rather than smoothing them all indiscriminately.
