Caps is a fantastic key to use for things like backspace, but if you want even more functionality, try using it with Colemak as a modifier that puts all the other common keys right on your home row: http://forum.colemak.com/viewtopic.php?id=1467
Slap that on a Truly Ergonomic keyboard (https://www.trulyergonomic.com) and you're living my life. Do it all at once and type 4 wpm for a month.
(I have the older "international" version with a number of blank keys. I remapped the left space bar to command and the lower left dead key to hyper. Tapping either shift of course generates a paren.)
I do use it as backspace (I got the idea from Colemak, which I didn't like that much, but I found this particular idea great). It's very convenient especially for deleting entire words (it's ctrl + backspace normally, but ctrl + capslock only requires one hand and it just feels easier).
