We've historically constrained the block size because it was the most logical thing to do. Bigger blocks take longer to propagate, and needed to be stored by all nodes. However we are quickly coming upon a future where bigger blocks can propagate at the same speed as smaller ones (IBLT) and full nodes can prune.
So instead of constraining the block size, how about we constrain the growth in UTXO. For instance we could constrain the each block to being able to increase the the UTXO set up to a fixed amount (e.g. 100 KiB).
Now instead of miners selecting for the most fees for the size, they would select for the most fees per growth in utxo. Many transactions decrease the UTXO, which is miners would strongly prefer. It wouldn't even be hard to imagine miners paying to accept a transaction that dramatically decreased the UTXO set.
We'd still need a very large block limit, to stop miners creating spam blocks (although they'd have huge incentives not to: they would have slow block propagation if they created a block full of crap that wasn't already on the network)
Topic: Shower-Thought Idea: Constrain UTXO set growth, not blocksize (Read 630 times)
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