I've personally never seen I/JKL before and over the years I've come to believe Vim made the right choice by use HJKL on the 'home row', so I might be biased. I can put my four fingers on all 4 keys at once with HJKL, but I can't with I/JKL.
This is a standard starting position (just shifted over one key left):
The average writer has probably never seen hjkl navigation before, and it is much harder to get used to than a slightly off-center "i" key.