I wrote a longer-form post here Polkadot: Blockspace over Blockchains | rob.tech which is worth discussing in the forum.
The short story is that we should be able to allocate the secure blockspace of the Polkadot network in a multitude of different ways, not just to long-term reserved slots. We would like to build out a number of these, like parathreads and short-term auctions, and allow projects to compose them into the blockspace they need.
Collators will be the purchasers of “Just-in-Time” or JIT blockspace used by parathreads, and any account should be able to participate in a short-term auction for blockspace. There is an interesting design space that emerges here which I’ll refer to as the “reimbursement layer”: ways that purchasers of blockspace on behalf of some chain can be reimbursed for their spend. I think the key insight here is that reimbursement for blockspace purchases can happen outside of the chain which received the blockspace.
Let’s discuss the topic of blockspace, blockspace allocation, collators, and reimbursement products here.