Comment by adornKey

I feel the problem. When coding (not only in SQL) you often have to add something to the end of a list, and it is annoying that the end of the list is always special. You can't just copy some line and move it there. Also when moving things around you always have to take extra care at the end.

So, my solution for this was always

  SELECT a
       , b
       , c 
  FROM ...

instead of:

  SELECT a,
         b,
         c,  -- people want to allow trailing comma here
  FROM ...

Leading commas also are also very regular and visible. A missing trailing comma is a lot harder to see.

Before people start to mess with the standard, I'd suggest to maybe just change your coding style - and make the start of the list special - instead of the end.

I'd suggest going for a lot less trailing commas - instead of allowing more.