As other people have said, it seems like you're suggesting p2panda + EBT.
I'm not so keen on breaking changes, I think it's completely non-trivial (almost mystical) how to get traction, and especially high quality traction. SSB at the moment has that. For some reason, we have a great and authentic community that keeps growing organically, and this has to take priority over any other technical improvement.
That said there are lots of ways of going forward which will mean breaking changes, but at least we can deploy them gradually and piece-wise, instead of the dramatic big rewrite.
new feed format
I'm not sure if you're familiar, @Dominic, with our work on partial replication, but one of the things we came up with was metafeeds and they are encoded in a new binary feed format we called bendy-butt, because it uses
bencode (from bittorrent).
One of the great advantages of the metafeeds design is that it will allow creating subfeeds that use any feed format, so we're already preparing this system so that you can have a gabby grove subfeed or a bamboo subfeed. To some extent this support is already verified in unit tests.
ebt is one of the technically best parts of ssb, refactoring it to do binary wouldn't be hard.
If I'm not mistaken, @arj and @cryptix worked on updating EBT to support binary. It's here: https://github.com/ssbc/ssb-ebt/tree/master/formats
new feed format uses lipma
Yeah it would be possible to have a subfeed of a metafeed that uses bamboo, or something else with lipma links. Similar to how multiserver supports upgradability, I think it's important that we allow several feed formats, instead of locking down on a single feed format, even if today it seems like a great option, it might tomorrow show some problems. The metafeeds design allows this upgradability.