Personally, I enjoy etymology, and like it when languages like English and French preserve spellings that reveal the word's origins. To me, a lot would be lost if we were to adopt purely phonetic spelling. Whenever I see attempts at rendering English purely phonetic, it looks hideous.
Yes, English spelling/pronunciation can be challenging for non-natives (and sometimes natives), but all languages have their crosses to bear.
It only looks "hideous" because we have been taught to think of it as completely improper.
The only thing that would be lost is the difficulty of learning how to spell properly (and this counts for native speakers as well).
And it's not like there won't be old dictionaries and books to give a glimpse of what spelling used to be.