Bitcoin didn't invent the concept of pooling: https://en.wikipedia.org/wiki/Pooling_(resource_management). This is a Bitcoin Mining Pool, although it may not be your favorite kind, which is fixated on specific properties of computing contributions before finding a block. Pooling is just a general technique for aggregating resources to accomplish something. If you have another name like pooling that is in common use for this type of activity I would be more than happy to adopt it.

This sort of pool can hedge not only against fee rates but also against increases in hashrate since your historical rate 'carries' into the future as a function of the window. Further, windows and reward functions can be defined in a myriad of ways that could, e.g., pay less to blocks found in more rapid succession, contributing to the smoothing functionality.

With respect to sub-block pooling, as described in the article, this sort of design also helps with micro-pools being able to split resources non-custodially in every block as a part of the higher order DCFMP. The point is not, as noted, to enable solo mining an S9, but to decrease the size of the minimum viable pool. It's also possible to add, without much validation or data, some 'uncle block' type mechanism in an incentive compatible way (e.g., add 10 pow-heavy headers on the last block for cost 48 bytes header + 32 bytes payout key) such that there's an incentive to include the heaviest ones you've seen, not just your own, that are worth further study and consideration (particularly because it's non-consensus, only for opt-in participation in the pool).

With respect to space usage, it seems you wholly reject the viability of a payment pool mechanism to cut-through chain space. Is this a critique that holds for all Payment Pools, or just in the context of mining? Is there a particular reason why you think it infeasible that "strongly online" counterparties would be able to coordinate more efficiently? Is it preferable for miners, the nexus of decentralization for Bitcoin, to prefer to use custodial services for pooling (which may require KYC/AM) over bearing a cost of some extra potential chainload?

Lastly, with respect to complexity, the proposal is actually incredibly simple when you take it in a broader context. Non Interactive Channels and Payment Pools are useful by themselves, so are the operations to merge them and swap balance across them. Therefore most of the complexity in this proposal is relying on tools we'll likely see in everyday use in any case, DCFMP or no.

Jeremy