Hardfork Wishlist

A ponee

Major structural changes:

• "Flip the chain", instead of committing to new transactions, commit to the summaries of open transactions: [1] [2]

Cryptographic changes:

• Pervasive ECC public key-recovery to reduce transaction sizes (can be done partially without breaking compatibility completely)
• Support for a post-quantum signature scheme. Lamport signatures have nice intuitive security properties, but it and all other similar schemes have extreme space requirements that would require structural changes to the blockchain to accommodate.