So if you dont like the term mempool, how about unconfirmed transaction pool, as long as you know what Im talking about. I understand the transactions are not received at the same time by all nodes and miners, thats why I brought up as a requirement that the content of the next block has to be agreed upon early enough. And no, the blockchain still has its value since the content is only then secured with the proof-of-work requirement.
I guess the concept is easier to visualize when we have an unconfirmed transaction pool that is relatively busy. Imagine miners are all actively mining block number 1200 and have agreed to the content of block 1201. While they are mining 1200, miners (and nodes) are ordering - according to this established and agreed protocol - the other unconfirmed transactions (those not already included for block 1201) for block 1202. Once block 1200 POW is resolved, miners starts mining block 1201 and it also means block 1202 content is fixed and the network is working on establishing block 1203s content.
This indeed imply the content of the next 2 blocks are fixed (the one being mined, and the one following it), only their headers to be established. It also means while block 1200 is mined, any fresh new transactions can expect at best to be included in block 1202 at the earliest. This introduced delay is required as the content of the next block (1201) has to be settled and ready since POW on 1200 could be resolved at any time.
In essence, this forward planning and ordering has some elements of proof-of-stake where the incentive - as a miner - is to participate and benefit from this coordination. Other miners would be left behind catching up at assembling the set of transactions when it comes time to start mining the next block. Consequently participating provides miners the ability to save precious time in the race for the next block.
And as stated before, users would also benefit since nodes would display the expected content of block 1200 (currently being mined) and 1201 (immediate block afterwards), and the work in progress for block 1202.
PS: I have unscrambled eggs regularly for breakfast