I've been working on the new user interface for Emvi [1] for the past three months or so and once you have build the muscle memory, you can use it blindly. You can read about it here [2] if you like and find current screenshots/gifs on Twitter [3].
One thing that might have turned people away from learning keyboard controls is that they get overwhelmed by a ton of different shortcuts. We (hopefully) solved this issue by using commands (words) you can type out instead of remembering two or more keys.
[2] https://emvi.com/blog/a-new-experimental-user-interface-QMZg...
Other than that issue, Zim is brilliant. The developer is very responsive to most issues and feature requests. Sadly, Zim wasn't for me as many of my notes involve code.
Here's a bug someone filed that hasn't even so much as gotten a response after nearly eight months:
https://github.com/zim-desktop-wiki/zim-desktop-wiki/issues/...