:::I'm happy to accept your argument, but I have reservations about the name "imaginary unit".  Being a non-mathematician, but having been exposed to complex numbers since my school days and having explored algebras over fields and the like, I cannot remember having encountered this name before reading this article – maybe through finding it unremarkable.  I also (somewhat irrationally perhaps) dislike the name as "not quite right". A survey of name by type of text would probably settle it for me, though. —