The same argument against increasing the block size but even more so. It takes time for blocks to propagate across the P2P network, which puts smaller miners at

The same argument against increasing the block size but even more so. It takes time for blocks to propagate across the P2P network, which puts smaller miners at a disadvantage by increasing their orphan rate, which leads to miner centralization. I think that argument is even stronger against lower block times because latency (network, validation, etc) rather than bandwidth contributes the most to block propagation delays.