Man, best of luck: "simplicity" and "personalization" are in pretty tight tension. Should inspire some interesting solutions!

Yup, that's one of the reasons I've been quite hesitant to add any features of the past few years!

I think it boils down to:

- intuitive vs. learned design (think: a window with a big X button vs. a terminal;) - limiting scope creep (so far I've been ok with that in Enso)

So:

- the UI will have a hint of the additional features (more visible on the first load), BUT - it should be perfectly accessible, intuitive and visually appealing to new users (that's easy, because this app from a technical pov is a dumbed-down text field with autofocus on)

An almost perfect example for me would be Winamp/WMP in 2000-2010s. You'd know instantly how to play your MP3s on it, but if you're curious/bored enough, you could customize the hell out of it, make it yours.

Another one would be... a wallet with custom artwork! or, any small practical item that is often customized or personalized.

So, something that feels mine but is also transparent, doesn't get in my way.

(I'm still thinking about finding the right way to describe this concisely. If you have better examples -- shout)