no i don't think blasting is a good idea
Discussion
Why's that?
because its dumb and lazy. would be better if clients just got better at fetching things where they are located.
it also doesn't scale
Sometimes that works. Yakihonne does a decent job at outbox model, but many times it's slow. Can't always rely on fast retrieval or handling. Same with Nostur's autopilot feature, it doesn't always load notes quickly when it fetches from other people's relays. Whereas a feature that regularly broadcasts all events to as many relays as possible ensures the events might be on the relays someone uses before they even request them.
this started to make me think of a possible p2p gossip network design for notes you're looking for. hmm
I always thought from the start that relay implementations should have had mirroring by default. And it should have only been optional filters to block certain kinds or by hostname. That'd certainly help with redundancy and reach.
i don't think you would want all relays to be redundant with all other relays, that wouldn't scale. what would be cool is node pairs that have things they want from each other syncing just the things they need.