In Vim, :! cleans up the tty context and hands it off to the child program, to do whatever it wants, you can open any TUI program and it will work as expected. In Neovim, :! just uses a plain pipe. Actually I believe GVim has the same problem. Since both Vim implementations now have a built in terminal handling stack anyway, I wonder if that could be used to unify the behavior.

Just nvim. Neovim runs :! commands non-interactively, capturing the output in a pipe. vim, on the other hand, suspends itself and runs the command in an external shell.

This isn't a problem, really, for non interactive commands, but causes issues with interactive ones. I personally prefer vim's approach, though not enough to abandon neovim.