However, the recent discussion premised upon Citrea's Clementine Bridge evidences primarily that the relaying capabilities of the Bitcoin network itself are sufficiently useful for L2 designers that there is an incentive to bypass standardness restrictions for the sake of reliably promulgating data -- at least in the case of Citrea, they say they need to quickly and widely disseminate 140+ bytes of arbitrary ZKP data to recover from an invalid protocol state, and the utility of that ZKP data very quickly decreases after it has been confirmed and processed.

Does your proposal actually solve this problem?  Posting the 140 bytes of data to the blockchain works as a public bulletin board because the actual data within the block is what is ultimately guaranteed to be disseminated to all participants.  With your proposal, a transaction with an OP_RETURN containing a hash of data could end up being mined without the relevant transaction ever even being relayed through the Bitcoin network.