Re^3: If I was forced to program in another language, the Perl language feature I would miss most would be:

[ikegami]

That doesn't solve anything. It just moves the problem the trailing comma solves. Instead of making it harder to add at the end, it makes it harder to add at the front.

[tilly]

I beg to differ. You're far more likely to want to add to the end, so it is a big improvement.