New goal: read a NIP every day
NIP-01: Not really an "improvement" but rather the base of the whole protocol. It defines the client and the relay and the communication between them.
It's a simple event based model (not dissimilar to the CloudEvents spec). It focuses on "who" (pubkey and sig) said "what" (kind and content) "when" (created_at). The "where" is loosely associated with your chosen relay. The "how" is the Nostr protocol itself. The "why" is a much more philosophical answer.