> [email's] underlying experience didn’t evolve much
In stories of architecture, this is the beaten path that becomes the walkway.
> Is it worth continuing to explore this idea?
It has to be worth it to you.
If you open-source it, you get to articulate what's important and shift from doing to leading. That's a forcing function to state values that inspire people.
For me, UI is a frustrating 1:N problem, where 1 designer(s) make trade-off's for many users. You're bound to get some early accolades, but expanding surface area scales mainly to frustrating everyone in some manner.
I'd like a UI that settles per user or use-case: automatically pruning things I don't use and hoisting things I do, often adapting use-case driven patterns. (The eclipse IDE UI had workspaces suited to different activities, and Mylyn task-based UI which hide or highlighted resources in the workspace for a given task; and that task context could be shared, e.g., attached to a bug, so anyone working on the bug would see (only) the relevant files or methods.)
The key question is what's different now with AI. Email or DB forms are presenting data in ways you can arbitrarily explore.
But when co-working with others or AI, it's more about watching messages and command streams between users, agents, etc, with varying levels of detail. AI is more about queueing up and automating interactions with a given intent. So in this case I'd e.g., enforce a GTD workflow by making queues for simple or hard, with contingencies on approvals or work, spawning actions that reply, and some ways to correlate related streams. To scale you need completion functions, archives, task debt tracking, etc. so you're always starting with a clean slate but someone can always pick up where you left off.
The thing about email is that it has mostly outlived a bazillion contenders, because the data conventions are dead simple and it has relevance built in, where each message (should) start with next steps and provide necessary context (intent and context: sound familiar?). And they're queued in your inbox, giving you instant organization (urgent X important). Combine it with markdown...