What I'd really like to be added to Perl:
I'd like if there were a %C sprintf format that was like %g, but also did commafication on the integer part of the number(well, with a locale-specific thousands separator, so you get "." or " " as locale-appropriate). So I can just do printf "That file uses %C bytes.\n", -s $filename; and have it say, for example, That file uses 10,116,911 bytes.
(I know it would be a Good Thing if all of sprintf were rewritten to allow, say, overloading specific sprintf formats. But I see reason to wait for that. If I knew any C, I'd just have done this myself years ago and submitted the patch; but I don't know C.)
Another thing I'd really like:
I'd like if there were a file read-discipline that would auto-guess the encoding (at least as either UTF-8, UTF-16, or other), and also auto-guess the newline format.