I've thought about this, focused on keys, perhaps also a built-in available local relay that syncs with contacts, and basic kind 1 note viewing/browser with or without a key loaded (read-only like an rss reader), with a focus on accessibility and simplicity. Optimized for mobile, tablet, desktop and server environments and for use with hardware signers. Plugins or apps could be added to expand functionality to different types of notes from git collaboration, audio/video channels to custom LLM based feeds.