From the implementation point of view representing characters as symbols is a real performance issue, because you would have to allocate every character on the heap, and a single character would then take more than 32 bytes of memory.
I think that's an implementation detail. You could still somewhat keep the character type in the implementation, but write them "x" (or 'x) instead of #\x and making (type c) return 'string (or 'sym).
Or, if you take the problem the other way, you could say "length-1 symbols are quite frequent and shoudn't take too much memory -- let's represent them a special way where they would only take 4 bytes".
This would require some kind of automatic type conversions (probably at runtime), but characters-as-symbols seems doable without the overhead I thought it would lead to.
