If you are already in Normal mode there's nothing to escape from, thus it's entirely possible to navigate down two lines. I find myself typing q quite often in day to day programming (it appears in 'frequency', 'query', 'quote', all important in my application), whereas jj is a sequence that appears in ~four words in English %w{hajj hajjes hajji hajjis}
I did inoremap q, which is not too bad if you're typing English prose. But still.