Why does it matter if there's no standard location? Do you use the ; command that often in vim anyway that this would be an issue if it were mapped to \?
Ymmv but it unfortunately matters for me. I switch between my work PC and personal Macbook daily. The different positions for \ drive me crazy, but as least it's rarely used on Macs due to sane file paths. Using a moving key in Vim is a bad idea.
