Better sign a hash of the block than the entire block
Currently we sign the whole block. But the bigger the block the longer the time to sign it. This is an incentive to write the smallest blocks to have a significant chance to write next block.
That's why we should rather sign a hash. This hash might be complex, have a special structure like:
HASH#10892-958ce5eb07b7d4a9fd804c97bd2057e59dd1867869f0186d8eeef86802a8ebb224c9fc1d7d5dd00798efa724a3d7632095539b2135f0afb171b95de3ae6bd98e