I'm not surprised they killed it. Only a small percentage of masochists actually like that functionality. For everyone who has ever been totally screwed while filling out forms and such, it was an infuriating nightmare.
Backspace means BACKSPACE. As in, move the cursor BACK one SPACE and delete what is there.
See also: the spacebar. It literally means to insert a space, but in web browsers it scrolls the page down by one screenful (equivalent to a PgDn), are we going to throw this out, too, since people can be entering data in a form, accidentally tab out of it, and then scroll down, losing their place, or accidentally tab over to a button and activate it by hitting the spacebar?
Backspace to navigate back has been in place for decades in lots of programs, and I'd be willing to bet it's used more than you seem to think.