Thank you very much for this! This is helpful.
A quick note: This reminded me of a somewhat strange portion of the verse in the Dvayatānupassanā Sutta:
Knowing this danger,
Etamādīnavaṁ ñatvā,
that suffering is caused by saṅkhārā;
dukkhaṁ saṅkhārapaccayā;
through the stilling of all saṅkhārā,
Sabbasaṅkhārasamathā,
and the stopping of saññā,
saññānaṁ uparodhanā;
this is the way suffering ends.
Evaṁ dukkhakkhayo hoti,
I know 行 is the word used for saṅkhāra, so ‘forming’ / constructing perceptions makes a lot of sense here. After all, the advanced meditative states are said to be willed/produced by saṅkhārā, and insight into this leads to liberation. This section of Snp 3.12 used to confuse me, but I think it makes a lot more sense now: sankhārā drive the stationing of consciousness / perception to different stations (and then rebirth); the stopping of all that means no more produced establishments of consciousness.
The other thing is that the entire C. stanza seems to emphasize all perception generally as well. With visañña replaced by P. rūpa, the first line points to all general perceptions; the second to not forming/willing perception which is characteristic of higher meditative perceptive states; ‘all being stopped’ is clear (and matches with Snp 3.12); and the final line has P. saññā as the root of papañca (used idiomatically perhaps) → dukkha.
Perhaps, in regards to the final line and my above comments on papañcasankhā, this is referring (loosely) to how saññā (and being established within it) is the root of being entangled in the manifest [samsāra]/all kinds of proliferation → dukkha. The gradual cessation of perception and the force of sankhāra which drive consciousness to be established within it is the cessation of all that entanglement. As for the comparison to DN 15 and Snp 4.11, this would trace us neatly back to the ‘vortex’ between nāmarūpa/viññāna and tie this with the rebirth aspect, and is still quite similar to the 8 vimokkha (which mention form and formlessness → cessation extensively, and relate this to the stationing of consciousness). This further parallels Snp 5.7, incidentally, which refers to freedom from the ‘nāmakāya’ (which is mostly perception/feeling). More speculation.
As you say though—remarkably similar. The message seems to be almost identical practically speaking, although in the C. it is much more explicitly climactic and referring to awakening.
Thanks again! Mettā
EDIT: Looks like Norman also renders papañca as referring to ‘diversification’ here — relatively identical to ‘expanse’ or the proliferated ‘manifest.’ He renders it:
for that which is named ‘diversification’ has its origin in perception