It can't even search specifically for directories, as far as I can see, nevermind searching for files/dirs with certain permissions, ages, etc.

It's also uselesss for non-interactive uses such as scripting.

I like fzf, but it's really not anywhere close to a complete find replacement.

I suspect the GP meant that fzf replaced the pattern 'find |xargs $binary' for small interactive use cases. It's much nicer to do '$binary <invoke fzf>'. I use fzf the same way with key bindings to select directories and files powered by find.

fzf just actually calls find by default, so a naked call to fzf will actually give you the same results as find | fzf.

Search specifically for directories, that's find -type d | fzf.