Sadly, this is the general trend with neovim in general: less focus on stability, more and more focus on shiny new things. If I didn't have an nvim config that I'm used to I would have switched to plain vim ages ago.
The Neovim developers have been extremely clear that part of the process of getting to 1.0 is finalising the API, and that there will be breaking changes en-route.
To be clear, it's fine to have breaking changes. Especially if you're working towards something substantial.
But nvim and its plugin ecosystem seem to be altogether too keen to change absolutely everything and adopt all bleeding edge developments. Even when a mature system would serve the purpose just as well.
But the UI is also an interface, and the user is part of the total system. That system interface is broken if you change default mappings.
It doesn't matter if the interfacing component is software or a user.