We did actually run into D1 issues during the outage, though I don't remember exact details on what was down. Our issues may have been API related with reads still functional.

My concerns, and this is very much my own concerns with no context of what has or is happening internally st Cloudflare, is that the outage exposed some serious issues that will take time to fix safely. The fact that D1 still doesn't support replication is an indication to me that it has been deprioritized, likely with other newer and less used products, while the infrastructure updates are dealt with.