Personally, I think this is an excellent change. If neovim remains 100% compatible with vim, down to every minor issue, then it will be very hard to usefully improve.

Personally I don't use vim, even though I like the concept of vim, because it simply doesn't fit with the ecosystem I want to use (it seems to be hard to integrate clang for auto-complete and syntax highlighting into vim for example, without long hangs or strange visual effects for example, because vim doesn't support threading for example)