I've been using web-browsers since the dawn of light. All browsers have supported "backspace" to go back to the previous page. I've read somewhere that "it is intended that backspace functionality is removed"?! Apparently due to some ppl accidentally goes back a page when they're writing something.
Just stop there for a moment and re-think.
If you ACTUALLY is writing something, then you have both hands ( usually ) on the keyboard and your mousecursor have placed the typing-cursor-line-thingy ( the blinking "|" ) inside a textbox of any sort. In this "writing-mode" the browser will never ever go back a page when using backspace.
If you're NOT writing anything ( there is NO blinking cursor ), then you have nothing to erase, therefore no logical reason to use backspace to erase any text?! AND, if your intention IS to back a page, and you're accidentally still in a textbox, you'll only erase one ( if any ) sign in that particular textbox instead of back a page.
So, lets see this from an ergonomically and logic pont of view:
Those who THINK they're about to erase some text, and accidentally back one or a few pages. They're not using their computer correctly ( or more correctly, they have not full control of WHAT they're really doing. Like 70+ yrs or <5 yrs and those who have no or very very little experience with computers ).
All others that have been introduced correctly to a computer ( or in this case, ONLY in how to use a webbrowser ), like, the rest of the world, knows what is supposed to happend when pressing the backspace-key.
Example one: Most ppl is using the mouse with their right hand. And most mouses is a 2-3 button mouse. Left hand is usually not occupied with anything and is perfect for one-hand-one-key-operation for backing one page.
Example two: Some ppl is using the computer for.... self-pleasuring ( not a good example, although true ). One hand is controlling the computer, the second hand is occupied with other things. You just DON'T want to use that second hand on the computer.
Example three: no-reason-surfin'. You're bored, you're sitting at the computer just to make the clock go. Left hand is supporting the chin and head, while the right hand is using the mouse to scroll, click, and sometimes use backspace to go back a page because that is way faster than try to hit that small go-back-button in the topleft corner. The two-hand-combo is forcing you to let go of your head/chin which is more annoying than mosquitoes a humid summernight.
Example four: Backspace placement vs. alt-left placement. Backspace is easy to find without looking on the keyboard, ANY keyboard. Top right of the big button-cluster, always above the enterkey and have always two sides free ( except from some laptops ) which makes it incredible easy to find. Also, backspace + any of the connected buttons won't do any harm if you accidentally presses both at the same time.
The alt-key alone is between the windows- and space-key, also directly touching atleast 2 character buttons. With only one side free, which makes is harder to find without looking, and can be slightly disoriented ( touching x-c instead of z-x for example, the spacebutton-size can differ ). Makes it easier to accidentally press "windows" or alt+space, which BOTH requires atleast ESC or mousebutton to be corrected.
The left-key is often used as more things than just moving cursor left, go back combined with alt, move active window to the half left screen combined with windows, some fn-function combined with fn and more...
Therefore, "alt" and "left" combined will cause far more accidentally actions and irritation than backspace is causing for those who don't know where in a webpage their focus is ( they THINK they're in a textbox, but is really outside it ).
I suggest you have that backspace as a standard, and alt-left as an optional alternative clearly visible in settings.
There is probably a lot lot lot of ppl between ages 5-70 that is expecting "this-is-how-it-always-have-been-working-before".
Best Regards - Pelle ( epoxxy )