Personally I don't have the backspace key remapped to another. Actually I think the important point about your question is how you use the different modes of Vim:
backspace erases characters only in insert mode which is only meant to insert text and do really minor changes to the text: This mean that you're supposed to use backspace only to erase 1 or 2 characters while you are inserting a new word.
If you need to erase more text, that means that you are supposed to switch to normal mode (or occasionally visual mode). The normal mode is meant to do bigger changes to your text:
- If you need to erase a whole line you'll be able to use
dd and if you need to erase the end of the line you'll be able to use
- If you need to erase the last 4 words you wrote you'll use d4b to say to Vim: "Use the
- If you need to erase until a specific character (let's says
a) you'll be able to use
T in commands likes dFa to say "delete until the last
a in the line"
So I think that you don't actually need to remap backspace because you're not meant to use it extensively.